AR-15 Buyers Guide: A Comprehensive Breakdown of the Revolutionary Firearm

Are you in the market to buy your first AR-15? Are you looking to expand your arsenal, but aren’t sure what you’re looking for? We’ve compiled the most complete AR-15 buyer’s guide out there to help you in your quest.

In this comprehensive guide, we’ll cover everything from the basics to advanced topics, with tips and tricks to enhance your shooting skills,  whether you’re a novice or an expert. Get ready to become an AR-15 pro! 

There’s a lot of info here. Want to skip ahead to another section? Just click the link in the table of contents so you don’t have to scroll through everything.

Why the AR-15?

You may be asking why the AR-15. Why is it the dominating choice for gun enthusiasts and firearm professionals? 

As with everything, there are a plethora of reasons, but it really comes down to three main factors. 

Modularity

The AR-15 offers a highly adaptable platform that can be easily customized to suit various purposes, such as hunting, target shooting, or self-defense, making it an ideal choice for different users.

Photo Credit: wideners.com

Think of it like legos. There’s an endless number of ways to configure your setup. 

Reliability

Known for its consistent performance and durability, the AR-15 can withstand harsh conditions and heavy use, ensuring it remains a dependable firearm choice for enthusiasts and professionals alike. 

Ergonomics

The AR-15 stands out for its lightweight and ergonomic design, providing a user-friendly shooting experience suitable for a range of abilities. With its mild recoil when chambered in 5.56x45mm and ease of handling, it becomes a more attractive option compared to other well-known rifles, such as the AK-47.

The History of the AR-15

While working for ArmaLite, a small arms engineering firm, American engineer and firearms inventor Eugene Stoner designed the AR-15. The term “AR” in AR-15 stands for ArmaLite Rifle, contrary to the common misinterpretation as “assault rifle.”

The creation of the AR-15 was prompted by the U.S. military’s need for a new infantry weapon to replace the M1 Garand, M14, and other service rifles. Stoner’s innovative design employed advanced aerospace materials like aluminum alloys and plastics to construct a lightweight yet sturdy rifle. The AR-15, chambered in .223 Remington (5.56x45mm), offered lower recoil, enhanced accuracy, and superior ergonomics compared to its forerunners.

Facing financial challenges in 1959, ArmaLite sold the AR-15 design to Colt, an American firearms producer. Colt modified the design and ultimately introduced it as the Colt ArmaLite AR-15. The U.S. military later adopted a fully automatic version of the rifle, called the M16, which was extensively used during the Vietnam War.

The original semi-automatic AR-15 became available to civilians, gaining immense popularity among firearm enthusiasts, sport shooters, and hunters. As time passed, various manufacturers developed their own versions of the AR-15, making it one of the most recognizable and prevalent firearms in the United States. The rifle’s versatility and adaptability have secured its lasting appeal as a cornerstone in the firearms industry.

How an AR-15 Works

In this section we’ll discuss the mechanics of how an AR-15 works.

The Firing Cycle

The firing cycle is a crucial process that allows the AR-15 rifle to function.

It starts when the shooter pulls the trigger, causing the hammer to release and strike the firing pin. This, in turn, ignites the primer on the cartridge, creating a spark that ignites the gunpowder inside the casing. The burning gunpowder creates high-pressure gases that propel the bullet down the barrel and out of the muzzle.

At the same time, the expanding gases push the bolt carrier group (BCG) backward, unlocking the bolt from the barrel extension and allowing the spent casing to eject out of the ejection port. As the BCG moves back, the recoil spring is compressed, and when it reaches its maximum rearward position, the spring pushes the BCG forward, chambering a new round from the magazine and locking the bolt into place.

This process repeats itself as long as the shooter continues to pull the trigger and feed cartridges into the rifle.

The firing cycle of an AR-15 is a carefully choreographed series of events that must occur in perfect synchronization for the rifle to function properly. Any disruptions or malfunctions can lead to a misfire or even catastrophic failure, which is why proper maintenance and care of the rifle is essential.

Understanding the firing cycle is not only important for proper maintenance and care of the rifle but also for shooters to improve their accuracy and precision. By knowing how the rifle functions, shooters can better anticipate recoil and adjust their aim accordingly, leading to better shot placement and overall performance.

How the Trigger Works

The trigger is an essential part of the AR-15 rifle that enables the user to fire the weapon. It’s a complex mechanism that consists of springs, wires, and bars that allow the firing pin to be released, which then sets off the primer, igniting the gunpowder inside the cartridge.

AR-15 triggers come in different types, based on their mode of installation and function. For instance, the standard mil-spec trigger has to be assembled before it can be installed inside the rifle, whereas drop-in trigger assemblies come encased and can be installed with ease. Based on their operating mechanism, AR-15 triggers can be single-stage or dual-stage.

The point at which the trigger releases the hammer is called the “break,” and the pressure required to achieve this is called the “pull weight” of the trigger.

A single-stage trigger requires the shooter to pull it all the way back until it reaches the specified or set break weight. In contrast, a double-stage trigger breaks in two stages. The first stage requires a heavier pull, which allows the shooter to confirm that they’re ready to take the shot. The second stage requires a lighter pull to minimize movement when pulling the trigger. This mechanism was developed to enhance accuracy even further.

Dual-stage triggers are mainly used by competitive shooters or for precision applications where shot placement is critical. Additionally, there’s a special kind of enhanced AR-15 trigger known as the “echo trigger” or “binary trigger.” This trigger fires a shot when pulled and another shot when released, allowing the shooter to fire two shots with a single trigger pull and achieve a faster rate of fire. It’s a clever alternative to a full auto AR.

Some trigger options allow the shooter to adjust the pull weight by using different springs or simple screw adjustments. These adjustable triggers are slightly more expensive than standard ones but offer greater customizability.

Factors such as pre-travel, over-travel, and creep must also be considered when choosing a trigger for your rifle. The lesser the value for these factors, the smoother a trigger operates.

The most common trigger pull weight for standard AR-15 rifles is between six to nine pounds. While that may seem heavy to some, it’s an optimal weight for stressful situations where the trigger must be heavy enough to prevent the shooter from flinching and accidentally firing a shot under panic.

The Gas System

The gas system is a vital component of an AR-15 rifle that plays a crucial role in its operation. After the bullet is fired, the cartridge casing is ejected from the ejection port, and the gas generated by the burning of gunpowder is used to cycle the rifle’s action.

The AR-15’s gas system works by directing the expanding gases through a gas port located on the barrel, into a gas tube that runs over the barrel and into the upper receiver. The gas then enters the gas key of the bolt carrier group, causing the carrier to move rearward and cycle the action.

There are two main types of gas systems used in AR-15 rifles: direct impingement and gas piston.

Direct impingement is the original gas system design used in the AR-15, where the expanding gas directly impinges upon the bolt carrier group to cycle the action.

Gas piston systems use a piston located near the gas port to cycle the action. Direct impingement systems are generally simpler and more lightweight than gas piston systems, but they can be more prone to fouling and heat buildup.

Gas piston systems are more reliable in harsh environments and easier to clean, but they can be heavier and more expensive than direct impingement systems.

Overall, the gas system is a critical part of an AR-15 rifle, and it’s important to choose the right system for your needs. Whether you prefer direct impingement or gas piston, ensuring that your gas system is properly maintained and functioning is essential for optimal performance and reliability.

AR-15 Parts Diagram: A Revolutionary Modular System

The AR-15 receiver is the critical component that receives and integrates all essential parts of the firearm. Receivers are typically constructed from 7075 T-6 or 6061 aluminum using forging, casting, or billet machining methods. Forged receivers are known for their strength, while machined receivers offer greater customization options for aesthetics.

The AR-15 consists of two receivers, the upper and the lower, each containing significant components that combine to create a complete firearm.

The Lower Receiver

The lower receiver is a vital part of the AR-15 rifle that serves as the lower portion of the receiver assembly. It houses the trigger assembly, grip, stock, buffer connecting areas, and the magwell.

According to U.S. law, the lower receiver assembly is considered the firearm.

One of the most impressive features of the lower receiver is its ability to function as a multi-caliber component, allowing for the creation of AR rifles in various calibers. This modular design allows for quick and easy caliber changes, making the AR-15 platform highly customizable and unique.

Builders can assemble their lower receiver by either purchasing a lower parts kit or choosing individual components of their choice. There are also different sizes of lowers available for AR-15 pistols or short barrel rifles.Lowers can be made from different materials, with 6061 T-6 and 7075 T-6 aluminum being the most common. The latter is almost twice as strong as the former, but also more expensive. Polymer lowers have also gained popularity due to their low weight, customization options, and affordability.

When choosing a lower receiver, it’s important to consider whether to go for a complete, stripped, or 80% lower.

Complete lower receivers come fully assembled with all the required components and are easy to work with, but are also more expensive and offer less customization options.

Stripped lower receivers are machined lower receivers with no components, providing more customization options for those building their rifles.

80% lower receivers require some machining by the buyer to accept the trigger and magazine, but were designed to bypass serialization laws for lower receivers. Lower receivers also differ in design, with some models featuring an ambidextrous design, allowing the controls to be operated from the right or left side.

All in all, the lower receiver is a highly important component of the AR-15 rifle that provides a great deal of customization and versatility, making it a favorite among firearm enthusiasts.

The Upper Receiver

The upper receiver, often referred to as the “upper,” is the top half of an AR-15 rifle and houses the most critical components of the firearm. This includes the bolt carrier group, gas system, charging handle, and barrel, along with other accessories like the handguard and top rail.

There are four types of AR receivers, denoted by the military as A1, A2, A3, and A4. The A1 model is the earliest type, and subsequent models are modified versions of it. The A1 and A2 models are easily distinguishable by their top carry handle design, while the A4 is the latest iteration.

AR uppers come in various configurations, with some featuring a forward assist and others omitting it. Additionally, some models come equipped with a top picatinny or weaver rail, and most have an ambidextrous charging handle in the proprietary AR style. However, some customized models may offer unique features such as side charging handles and ejection ports for specific left or right-handed builds.Since the upper receiver is not a legally classified firearm component, it can be obtained easily without the need for an FFL or background check.

Like lower receivers, AR-15 uppers come in complete or stripped variants. However, due to legal limitations, there is no 80% design option for uppers.

A complete AR-15 upper includes the necessary components for building the upper part of the rifle, including the BCG, barrel, and charging handle. This plug-and-play option is most commonly used for quick caliber swaps on an AR-15 rifle.

Alternatively, stripped uppers allow for a greater degree of customization and allow the user to choose the internal components that best suit their needs. These are often favored by experienced builders who want to create a fully customized rifle.

By simply mating a different upper with the lower, the AR-15 can fulfill various roles ranging from a long-range precision rifle to close-quarters combat (CQB).  Since only the lower is the serialized firearm, you can have several uppers to fulfill any role without additional paperwork.

AR-15 Barrels

The barrel is a critical component of an AR-15, as it directly affects the rifle’s accuracy, range, and overall performance. 

The barrel is the tube through which the bullet travels, with its interior being rifled to induce a stabilizing spin on the projectile. Factors like length, chambering, twist rate, material, and lining all impact how an AR-15 barrel performs, which is why understanding these aspects is crucial for selecting the best AR-15.

Barrel Chambering:

In an AR-15, the section of the barrel that holds the cartridge before it’s fired is known as the barrel chamber. This part dictates the ammunition type the rifle can utilize. 

For those new to AR-15s, we’ll focus on the two most prevalent chamberings: 5.56x45mm NATO and .223 Remington. 

It’s important to note that many other chambering options are available, ranging from .22LR to .50 Beowulf, as well as a host of emerging .30 caliber alternatives. More on that to come later.

Between the two most common options, the 5.56 chamber is often the preferred choice, because it offers more forgiving tolerances and is capable of withstanding the increased pressures produced by the 5.56 round.

Specialized hybrid chambers, such as the Wylde chamber, are designed for precision shooting and can handle both 5.56 and .223 rounds.

BOTTOM LINE: we recommend you look for a 5.56 NATO rifle to start with as this is the most standard configuration and can utilize both 5.56 and .223 ammo. 

Barrel Lengths:

Federal law mandates that a rifle’s barrel must be at least 16 inches in length, including any permanently attached muzzle devices like flash hiders, muzzle brakes, or compensators. To be considered permanent, the device must be pinned and welded to the barrel. 

For instance, a 14.5-inch barrel with a permanently attached muzzle device that extends its length past 16 inches is compliant. However, be aware that state or local laws may impose further restrictions on barrel lengths and muzzle devices.

For beginners, we recommend choosing a 16-inch barrel to allow for easy swapping of muzzle devices. Common barrel lengths include 16, 18, and 20 inches. 

But which one is the best for you?

While longer barrels don’t necessarily guarantee greater accuracy, a 16-inch barrel offers adequate accuracy due to its stiffness and reduced susceptibility to barrel whip (movement during shooting). 

However, longer barrels provide increased velocity since there’s more space for powder to burn, allowing the bullet to travel faster. This higher velocity means environmental factors such as gravity and wind have less time to affect the bullet’s trajectory.

A typical 16-inch barrel is effective up to 400 yards, but beyond 300 yards, the standard 55-grain projectile becomes more vulnerable to environmental influences. For shooting at longer distances, heavier and longer bullets like 62gr, 77gr, or 80gr projectiles are recommended.

Portability is another factor to consider. Shorter barrels are easier to maneuver and lighter in weight, making them more suitable for various situations.

Barrel Twist Rate:

When examining AR-15 barrels, you’ll notice a twist rate associated with the rifling, expressed as a ratio like 1:9. This ratio signifies “one twist per 9 inches,” indicating the distance required for the rifling to complete one full rotation within the barrel.

In general, the longer a projectile, the faster the twist needed (a smaller number in the ratio), as this ensures one turn occurs in a shorter length, providing better stabilization for heavier bullets. The ideal bullet weight for a specific twist rate can be determined using reference charts.

Among AR-15 barrels, the 1:9 twist rate is prevalent due to the widespread availability of 55-grain ammunition. In contrast, the most common mil-spec twist rate is 1:7, as it provides better stabilization for longer and heavier tracer rounds used by the military. The twist rate is normally engraved on the barrel by the manufacturer. 

Understanding the relationship between twist rates and bullet weights is essential for choosing the right AR-15 barrel. A suitable twist rate ensures optimal bullet stabilization and accuracy, enhancing the overall performance of the rifle across various shooting scenarios.

Just remember, the smaller the number, the faster the twist.

Barrel Material:

Navigating the world of barrel materials can seem overwhelming due to the numerous technical terms and numbers. However, we’ve broken down the key points to help you understand the basics:

4150: This steel type is utilized in mil-spec barrels and offers a more robust option.

4140: Containing 10% less carbon than 4150, this steel is slightly less durable but still a popular choice.

Chrome Molybdenum Vanadium (CMV), Chrome Moly: These terms refer to the same material as 4140 steel.

Stainless Steel: Known for its increased accuracy, stainless steel barrels generally have a shorter lifespan.

For most casual shooters, opting for a 4140 or CMV barrel is a solid choice. Unless you’re frequently firing in full-auto mode, the benefits of a 4150 steel barrel may not be significant enough to justify the additional cost. By choosing a 4140 or CMV barrel, you can maintain solid performance without breaking the bank.

Barrel Lining:

Chrome-lined barrels are known for their durability and longevity, but they may come at the cost of a slight decrease in accuracy. These barrels are easily identifiable by the gray ring around each end. If you prioritize barrel life over absolute precision, chrome-lined barrels are a solid choice.

Ferritic Nitrocarburizing (FNC) is another option, often referred to as Tennifer, Melonite, or Nitride. This treatment process alters the surface of the barrel, rather than applying a coating. FNC-treated barrels offer improved accuracy compared to chrome-lined barrels, but they may also come with a higher price tag.

Uncoated barrels represent a more basic choice, with no specific lining or treatment applied. These barrels may not have the same level of protection against wear and corrosion as chrome-lined or FNC-treated barrels, but they can still be an option for casual users or those on a tight budget.

It’s essential to note that the actual round count before needing to replace a barrel depends on various factors such as heat, environment, and one’s definition of “accuracy.” Generally, you can expect somewhere between 10,000 to 20,000 rounds before a re-barrel may be necessary.

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Barrel Testing:

Barrel testing is essential for ensuring the reliability, durability, and accuracy of an AR-15. Manufacturers employ various testing methods and may use specific acronyms to indicate the testing procedures applied to their barrels.

MP (Magnetic Particle) testing involves magnetizing the barrel and using fine iron particles to detect cracks or defects. This process ensures that your barrel is free from any imperfections that could compromise its performance.

HP (High Pressure) testing subjects the barrel to pressures higher than standard operating conditions to ensure it can withstand the rigors of firing. This is particularly important for a home defense rifle, where you need to rely on the weapon’s performance in critical situations.

Some barrels may not be tested at all, which means you’re taking your chances when it comes to quality and reliability. Keep in mind that “you get what you pay for,” and investing in a thoroughly tested barrel is often worth the extra cost.

Be cautious of “batch tested” barrels, as this term can be vague. It may mean that the manufacturer tested only one barrel out of every 10, 100, or even 100,000 produced. The consistency and quality of these barrels may vary, so it’s wise to opt for a barrel that has been both MP and HP tested.

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Barrel Forging:

Cold Hammer Forged (CHF) and Barrel Forged Hammer (BFH) are two methods employed in the production of AR-15 barrels that prioritize durability. Although these processes are essentially the same, they both result in a stronger and more long-lasting barrel, making them ideal for heavy use.

While CHF and BFH methods might slightly reduce accuracy compared to other barrel manufacturing techniques, the trade-off is a significantly more durable barrel that can withstand extensive firing. 

If you plan on shooting thousands of rounds per year, the extra investment in a CHF or BFH barrel may prove worthwhile, potentially extending your barrel’s lifespan to over 20,000 rounds.

In contrast, opting for a barrel without these additional processes may offer slightly better accuracy, but it could also mean sacrificing long-term durability. 

Ultimately, the choice between CHF, BFH, and non-treated barrels will depend on your shooting requirements, personal preferences, and intended usage.

Barrel Contours:

Contour refers to the barrel’s thickness and overall shape, which play a critical role in the rifle’s performance, accuracy, and heat dissipation. There are four main categories of barrel contours: lightweight, government, medium, and heavy profiles.

Lightweight: This class includes featherweight and pencil barrels, which feature reduced wall thickness. These barrels are an excellent choice for shooters who frequently fire without support, as they minimize the rifle’s overall weight.

Government: A hybrid class that combines elements of lightweight, medium, and heavy barrel contours, the government profile is designed to accommodate an M203 grenade launcher cutout. This versatile contour is suitable for a wide range of applications.

Medium: Similar to lightweight barrels, medium profile barrels are an all-purpose option that offers improved heat soak mitigation. This balance between weight reduction and heat management makes them a popular choice for various shooting scenarios.

Heavy: Also known as bull barrels, heavy profile barrels boast the thickest barrel walls, resulting in greater accuracy and superior performance during full-auto fire. While these barrels provide enhanced rigidity and heat dissipation, they also increase the rifle’s overall weight.

Barrel Feed Ramps:

The barrel feed ramp is an essential component of the AR-15, responsible for guiding a new round from the magazine into the firing chamber. 

There are two primary types of feed ramps for AR-15s: standard and extended. It is crucial to ensure that the ramp type corresponds with your upper receiver for optimal performance and reliability.

Standard feed ramps, often associated with A3 or A4 rifle profiles, are the traditional choice for many AR-15s. 

Extended feed ramps, commonly referred to as M4 profiles, provide an elongated surface to facilitate smoother round feeding. 

While the debate continues about the tangible benefits of M4 ramps for reliability, the critical factor is matching your feed ramps with the upper receiver.

When purchasing a factory-made rifle, these compatibility issues are less likely. 

In conclusion, the barrel is a critical component of the AR-15, affecting accuracy, range, and durability. AR-15 barrels come in various profiles, materials, finishes, and twist rates, offering many customization options to suit different shooting needs. Whether you’re a beginner or an experienced shooter, choosing the right barrel for your AR-15 is crucial for optimal performance.

Bolt Carrier Group (BCG)

The bolt carrier group (BCG), also known as the ‘action,’ is the engine that powers your AR-15, ensuring smooth and reliable operation. The BCG consists of the bolt and the firing pin, housed within the bolt carrier, and various other components.

The BCG is the key component for the cycling process of your firearm, from chambering a round to ejecting spent casings. It is also the most difficult part of the firearm to clean. 

To ensure the bolt carrier group (BCG) is designed to the best durability standards, manufacturers subject it to HPT (High Pressure Testing) and MPI (Magnetic Particle Inspection) testing.

Understanding the Role of the BCG

When you pull the charging handle back, the BCG moves back as well. Releasing the charging handle causes the BCG to move forward, stripping a round from the magazine and chambering it. 

Pulling the trigger releases the hammer, which strikes the firing pin housed in the BCG. This action ignites the primer, firing the round and propelling the bullet down the barrel. 

The gas system then comes into play, cycling the BCG to repeat the process.

Semi-Auto vs Full-Auto BCG: Features and Benefits

Semi-auto (SA) and full-auto (FA) BCGs are the two main types available for your AR-15. Contrary to popular belief, using a full-auto BCG doesn’t automatically make your firearm fully automatic. 

The primary difference between the two is the added mass in the FA BCG, which helps slow down the cycling rate. This additional mass can offer improved reliability, especially in over-gassed firearms.

Full-auto BCGs feature a shroud that protects the firing pin from the hammer during re-cocking. This design reduces the firing pin’s exposure and adds weight to the BCG, enhancing its durability and performance.

While both semi-auto and full-auto BCGs can perform well in your AR-15, many higher-end manufacturers opt for the FA BCG due to its increased mass and firing pin protection. These features are particularly useful in over-gassed firearms, which use more gas than necessary to ensure reliable cycling across various types of ammunition and in dirty conditions.

Lightweight BCGs for Competition Guns

In addition to standard BCGs, lightweight BCGs are available for competition firearms. These low-mass carriers reduce the overall weight of the AR-15 and often require an adjustable gas system for optimal performance.

BCG Coatings: Enhancing Performance and Durability

The latest trend in BCG technology is the use of specialized coatings, such as nickel boron, titanium nitride, hard chrome, and black nitride. These coatings claim to make BCGs easier to clean, require less lubrication, and run longer between cleanings.

Coated BCGs may be beneficial for those who frequently use their firearms, especially with suppressors that deposit more debris into the BCG. However, for most users, a regular, well-maintained BCG will suffice.

BCGs can vary in build and quality. For self-defense, operators may opt for a heavier, better-machined build, ensuring the rifle is available for use when it is most needed, such as for home defense or for troops. Competition shooters may opt for a lighter weight BCG for faster cycling times.

The Gas System

The AR-15 operates using a direct impingement gas system, which differs from other rifles, such as the AK-47, that use a piston system to cycle the bolt. While it is possible to customize an AR-15 with a gas piston system, this is not very common and may not fully utilize the capabilities of the platform.

When a round is fired, gases escape through a hole in the barrel and into a gas tube, which has a length referred to as the gas system length of the AR-15.

There are four available gas system lengths, each suited to a particular barrel length: rifle length for 20+ inches, mid-length for 14-20 inches, carbine length for 10-18 inches, and pistol length for barrels under 10 inches.

The gas block serves as an adapter between the barrel and the gas tube and can be either fixed or adjustable. Adjustable gas blocks offer the advantage of fine-tuning for different ammunition types and recoil mitigation. However, proper tuning technique is important to avoid issues such as overgassing or undergassing. Gas blocks are installed inside the handguard on the barrel, and gas tubes connect the block to the upper receiver. These components are part of the system that expels gas from the gun when a bullet is fired.

After the trigger is pulled, the bullet leaves through the barrel, the used round is ejected, and a new one is chambered. Simultaneously, the pressure forces gas through the gas port, inside the gas block, down the gas tube, and out through the bolt carrier’s gas key.

It is important to know the correct gas system length of your AR-15 to order the correct length gas tube and handguard. Some gas blocks are adjustable, allowing users to tune their rifle to minimize recoil.

In conclusion, the direct impingement gas system is a unique feature of the AR-15, with four gas system lengths available to match specific barrel lengths. The gas block serves as an adapter between the barrel and gas tube, and adjustable gas blocks offer the advantage of fine-tuning for different ammunition types and recoil mitigation.

Buffer & Buffer Tubes

The buffer is a critical component of the recoil handling assembly of the AR-15, responsible for cycling the bolt carrier group (BCG) forward into the battery after the blowback from the fired round pushes it backwards.

The buffer system in an AR-15 collectively refers to the buffer weight, tube, spring, latch plate, and castle nut, and plays an essential role in recoil mitigation and reliable feeding. The buffer weight, which is a hollow cylindrical piece of metal with a larger face that the recoiling BCG slams into, is the most important part of the buffer assembly.

There are two primary types of buffer tubes available for AR-15 rifles: commercial and mil-spec.

Commercial buffer tubes are typically manufactured from extruded aluminum, with a slightly larger outer diameter than their mil-spec counterparts. This makes them less expensive to produce, but potentially less durable. The threads on commercial tubes are cut at a 45-degree angle, and the rear end of the tube is slanted.

Mil-spec buffer tubes are made from stronger 7075-T6 aluminum and have a smaller outer diameter. The threads on mil-spec tubes are rolled, rather than cut, which creates stronger, more consistent threads. These tubes have a flat rear end and are designed to meet stringent military specifications, making them more durable and reliable.

The weight of the buffer is crucial and relative to the length of the gas system that your AR-15 is using. The buffer weight is filled with multiple smaller metal weights, and there are three primary types of buffer weights – carbine buffer (3 ounces), heavy buffer (3.8 ounces), and H2 buffer (4.7 ounces) – that are most commonly found in most AR-15 rifles with the respective gas system length. Heavier buffers such as the H3 (5 ounces), HSS (6.5 ounces), and XH (8.5 ounces) are also available, and are mostly used with short-barreled, overgassed (large diameter gas ports), and fast-burning AR ammunition, particularly with AR9 pistols.

Bottom Line: If you buy a pre-built AR, then you get what you get, but if you are building from scratch, go with a mil-spec buffer tube. You’ll need to match the carbine/rifle lengths to your chosen barrel, but the extra durability and reliability are worth it. 

The Rail System/Handguard

Handguards are essential components on long guns, serving a dual purpose of providing a gripping surface to handle the weapon and acting as a barrel shroud. On AR-15 rifles, handguards are classified as either drop-in or free float. The right handguard selection is crucial, as it enhances the weapon’s handling and accessory compatibility, while influencing accuracy through direct contact with the barrel.

AR-15 handguards come in a variety of designs, including simple ones with a plain texture, or more complex ones with rails on all four sides and a modular attachment system like Keymod or M-lok. Polymer handguards are preferable since they are lightweight and a poor conductor of heat. Metal handguards are also available, but they are heavier. AR-15 handguards and rail systems offer several benefits to users. Firstly, they protect the operator’s hands from the heat generated by the barrel during use, preventing injury. Secondly, they safeguard the gas tube, which is exposed on the outside of the barrel, from damage or snagging. Lastly, the rail system allows for attachments and firearm upgrades.

Two popular rail systems used by operators are the Picatinny rail system and the KeyMod system. The Picatinny rail system is an older and heavier system, while KeyMod is a more modern and lighter system with a lower profile, offering greater flexibility through its modular design. The M-LOK system by Magpul is also gaining popularity. Both systems have their pros and cons, but users can purchase small Picatinny rail mounts to use on KeyMod and M-LOK systems, providing the best of both platforms.

Upgrades and attachments available for rail systems include scopes, sights, mounts, sling attachments, grips, hand stops, and bipods. This flexibility and customization are among the primary reasons why the AR-15 platform is so popular and widely adopted.

AR-15 Triggers

The AR-15 trigger assembly includes a trigger, disconnector, hammer, and accompanying pins and springs. Standard AR-15s feature a one-stage trigger, which offers reliability and a clear break and reset, despite not being the smoothest or lightest option. There are many after market drop-in triggers available.

AR-15 triggers can also be categorized as either single stage or dual stage, depending on their operating mechanism. Single stage triggers break at their specified break weight, while dual stage triggers break in two stages, allowing the shooter to confirm readiness before firing. Dual stage triggers are typically used for precision applications where shot placement is critical, such as in competitive shooting.

Enhanced AR-15 triggers, such as the “echo trigger” or “binary trigger,” fire a shot when pulled and another shot when released, enabling the user to fire two shots with a single trigger pull and achieving a faster rate of fire. These triggers are a smart alternative to full auto ARs.

Some trigger options allow for pull weight adjustment using different springs or simple screw adjustments, offering good customizability. Factors such as pre-travel, over-travel, and creep must also be taken into consideration when selecting a trigger for your rifle, with smoother trigger operation being preferred.

The most common trigger pull weight for standard AR-15 rifles is between six to nine pounds, which may seem heavy to some but is optimal for stressful situations where the trigger should be heavy enough to prevent accidental firing under panic. AR-15 triggers are complex mechanisms of intertwined springs, wires, and bars that must be carefully selected and maintained to ensure optimal performance.

Many budget and mid-tier AR-15s come with single-stage mil-spec triggers, but advanced shooters seeking enhanced performance often opt for two-stage or match-grade triggers. These upgraded triggers require less pressure to fire, enabling more precise shots in competitions and long-range shooting.

If this is your first AR, we recommend sticking with the out-of-the-box option, so you can get a feel for how it works, which will help you make a more informed decision when you go to build from scratch. 

If you are building your first AR, or want to improve the one you bought, the trigger is one of the best upgrades you can make. You’ll be sure to notice the difference!

The Forward Assist

The bolt forward assist is a component of the AR-15 rifle that has been hotly debated among gun enthusiasts. Its function is to push the bolt forward in case of a malfunction, providing a quick solution to get the rifle back into operation.

The forward assist has been an integral component of many rifles, especially combat assault rifles like the M1 Garand. The forward assist on the AR-15 is a plunger button located on the right side of the rifle, just behind the ejection port. The pawl of the assist engages with the ratcheting teeth on the bolt carrier, allowing the bolt to be moved forward by one tooth with each press of the button.

The main reason for using the forward assist is for stealth purposes. By slowly releasing the charging handle and then pushing the last few millimeters using the forward assist, the shooter can avoid making a loud “clack” sound that may alert others to their presence. This can be useful in situations such as stealth combat operations or hunting wary game animals.

Interestingly, the AR rifle was initially adopted by the Airforce without a forward assist. After three years of evidence-based results, they deemed it unnecessary. Even Eugene Stone, the founder of AR, called it redundant. However, the Army, as the bulk buyer, wanted it as a psychological “quick fix” support for soldiers.

Today, both rifles with and without the forward assist are available. While not having one will not cause significant issues, many shooters still prefer having the option. Ultimately, the decision of whether to have a forward assist on an AR-15 rifle comes down to personal preference and intended use.

Charging Handles

The charging handle is a vital component of the AR-15 rifle that manually cycles the bolt carrier group (BCG). It is located at the rear of the upper receiver and is used to chamber a round and prepare the rifle for firing.

AR-15 charging handles come in various styles and sizes, including ambidextrous designs for both left and right-handed shooters. A good charging handle should be easy to grip and use, allowing for quick and smooth operation of the rifle.

One of the significant advantages of the AR-15 charging handle is that it can be operated with just one hand, making it an excellent option for hunters and shooters who need to keep one hand free.

Upgrading to an extended charging handle or one with an enlarged latch can improve accessibility for those using optics or other accessories that may obstruct access to the handle. However, using the charging handle incorrectly can cause malfunctions, preventing the BCG from properly engaging with the buffer tube. Proper training and practice can prevent this issue, along with using high-quality components.

Overall, the charging handle is a crucial part of the AR-15 rifle that should be chosen with care. It’s important to select a well-designed handle that is easy to use and maintain and to practice proper techniques to ensure optimal performance.

Ejection Port Covers

The ejection port cover is a vital component that helps keep the AR-15 rifle clean and functioning properly. When the gun is fired, the bullet’s case is separated from the action and expelled through the ejection port. Without a dust cover, the small particles from the discharge can accumulate and enter the rifle’s inner workings through the ejection port, potentially causing malfunctions.

The ejection port cover’s main purpose is to keep the rifle clean, ensuring that it operates as intended. The cover will automatically open when the gun is fired, allowing for the discharge of the casing, and then close to prevent dirt, dust, and other debris from dirtying the rifle. This keeps both the bolt carrier group and the upper receiver clean, which is essential for maintaining optimal performance.

In addition to its functional benefits, ejection port covers can also add some personal style to a rifle build, as they can be customized with graphics. Overall, the ejection port cover is an important component of the AR-15 rifle that helps ensure reliable performance and adds a bit of personality to the firearm.

Types of AR-15’s

As we’ve hinted at along the way, the type of AR-15 you buy/build will depend on your intended use. Here is a breakdown of the scenarios. 

Tactical

The most common AR-15 type is pretty straight forward. You intend to use it in a tactical setting, similar to a combat rifle like the M4 military carbine. 

Although the M4 generally sports a 14.5-inch barrel with a carbine length gas system, most AR-15 versions come equipped with a 16-inch barrel and a combination of carbine and mid-length gas systems.

Adjustable buttstocks are frequently used to tailor the length of pull and eye relief for individual preferences.

One version boasts a standard setup, complete with a carry handle, non-free-floating handguard, carbine gas system, and a front sight base.

On the other hand, the BCM model features a flattop upper receiver, a Picatinny rail on top, M-LOK rail on the sides, a free-floating handguard, mid-length gas system, and a streamlined gas block.

Both would fall into this category as they still perform the same job and can be used for the same purposes. 

Precision/Varmint

Precision and varmint AR-15 builds are typically intended for shooting small to medium-sized game. They will have heavier barrels, top-quality triggers, and long-range optics. 

Think Farmer Fred trying to keep the coyotes away from his chickens. 

These builds often feature 18- or 20-inch heavy contour barrels for enhanced stability and velocity. The twist rates and materials may be optimized for accuracy, with options such as 1×8 or 1×7 twists and non-chrome-lined or stainless steel barrels.

These builds are commonly associated with acronyms like Special Purpose Rifle (SPR) and Designated Marksman Rifle (DMR), signifying their longer barrels for improved range and accuracy.

Precision-focused AR-15s typically come equipped with free-floating handguards and more substantial buttstocks. The addition of a scope and a bipod is common, resulting in a significantly heavier rifle.

SBR/Pistol Builds

Short-barreled rifles (SBRs) and AR pistol builds offer compact alternatives to the standard AR-15 platform, prioritizing maneuverability and ease of handling. These configurations are ideal for personal defense or close-quarters combat, where larger rifles may prove unwieldy.

SBRs typically feature barrels shorter than 16 inches, whereas AR pistols utilize even shorter barrels, often coupled with a stabilizing brace rather than a traditional stock. This design allows for improved handling and portability while still maintaining the core functionality of the AR-15.

Muy importante. Check your local laws regarding SBR’s and pistols. An SBR requires paperwork and a tax stamp. The ATF  has made several changes to these laws in recent times and it is important you stay up to date with the current laws. 

Due to their compact nature, SBRs and AR pistols often employ shorter handguards and gas systems. Optics for these builds usually focus on rapid target acquisition, with red dot sights or holographic sights being popular choices.

Competition Builds

Competition builds for AR-15s are tailored to enhance performance in various shooting disciplines, such as 3-gun, precision rifle, or service rifle competitions. These builds prioritize accuracy, speed, and handling, ensuring a competitive edge for shooters.

Barrels in competition builds often feature lighter contour profiles and specialized materials, enabling quicker target transitions and improved heat dissipation. Adjustable gas systems are common, allowing for fine-tuning of the rifle’s performance according to the shooter’s preferences and ammunition choice.

Upgraded triggers, such as two-stage or match-grade triggers, provide a smoother and lighter pull, contributing to increased accuracy and faster follow-up shots. Free-floating handguards are typically utilized to reduce any potential interference with barrel harmonics, further enhancing accuracy.

Optics for competition builds are chosen based on the shooting discipline, ranging from red dot sights for quick target acquisition in 3-gun to high-magnification scopes for precision rifle events.

Lastly, lightweight components and ergonomic furniture, such as adjustable stocks and comfortable grips, improve handling and reduce shooter fatigue during competitions.

In other words, competition AR-15 builds are highly optimized for performance, accuracy, and handling. Shooters want every possible advantage in competition. 

Side note: CAT Outdoors was started by a competition shooter. 

PCC’s (Pistol Caliber Carbine)

Pistol Caliber Carbines (PCCs) are AR-15 variants designed to utilize pistol calibers, offering benefits such as reduced recoil, more affordable ammunition, and compatibility with certain handgun magazines. PCCs have gained popularity for plinking, competition, and home defense scenarios.

The AR-9 is a very popular option right now. 

PCCs feature barrels specifically designed for pistol calibers, often with a different twist rate and chamber dimensions compared to traditional AR-15 barrels. The bolt carrier group and buffer system may also be adjusted to accommodate the different pressures and cycling requirements of pistol rounds.

The use of pistol calibers results in a more manageable recoil impulse, allowing for faster follow-up shots and improved control during rapid fire. This characteristic is particularly advantageous in competitive shooting disciplines such as USPSA or Steel Challenge.

Optics for PCCs usually prioritize quick target acquisition and parallax-free operation, with red dot sights and holographic sights being popular choices among shooters.

PCCs maintain the modularity of the AR-15 platform, enabling customization with various furniture and accessory options, such as adjustable stocks, ergonomic grips, lights, and lasers.

In other words, it looks and feels like an AR-15, but uses pistol mags and ammunition. 

Featureless Rifles

You can thank CA and NY for this one.

Featureless builds cater to AR-15 enthusiasts in jurisdictions with restrictive firearm regulations, enabling them to enjoy the shooting experience while complying with legal requirements. These builds typically lack certain features considered “assault weapon” characteristics in some areas.

Common modifications in featureless builds include the use of fixed or “thumbhole” stocks to replace adjustable stocks, and the removal or replacement of pistol grips with compliant alternatives, such as grip wraps or fin grips, to maintain legal compliance.

Flash suppressors may be replaced with muzzle brakes or compensators that do not fall under the definition of prohibited muzzle devices, while the standard AR-15 magazine release is often substituted with a “bullet button” or other compliant release mechanism, requiring a tool for magazine changes.

Despite these modifications, featureless builds maintain the core functionality and modularity of the AR-15 platform. Shooters can still customize their rifles with compliant accessories, such as optics, handguards, and triggers, to optimize performance and aesthetics.

Should You Build or Buy Your AR-15?

For your initial AR-15 purchase, we highly recommend choosing a complete rifle from a trustworthy manufacturer. This ensures you receive a reliable firearm backed by a warranty, which eliminates potential issues and guarantees a well-built rifle. 

Pre-assembled firearms also tend to hold better resale value if you decide to sell or upgrade later.

As a beginner, you might be unsure about your preferences, so starting with a standard configuration is wise. A factory-assembled rifle’s cost is comparable to building one yourself and might even be lower. 

Although building your own AR-15 can be satisfying and educational, it may present challenges for novices due to the required technical knowledge and expertise.

Considering this is your first firearm purchase, opting for a pre-assembled AR-15 is advisable. This choice allows you to familiarize yourself with the platform, better understand your preferences, and hone your shooting skills. 

You could also explore options like purchasing a complete upper and lower, which can save you money since companies face an 11% tax on fully assembled firearms.

After spending time with a factory-assembled rifle and gaining more experience, you might want to consider building a custom AR-15 as a future project. This will allow you to select each component individually with the confidence of knowing precisely what features you desire. 

However, for your first foray into the world of firearms, a pre-assembled AR-15 remains the most practical choice.

Legalities and Disclaimers: What You Need to Know About Owning an AR-15 in the US

If you’re thinking about purchasing an AR-15, it’s essential to understand the legalities and disclaimers surrounding it. This semi-automatic rifle has been at the center of many discussions and debates on gun ownership and control in the United States.

To begin with, it’s important to note that Colt’s Manufacturing Company owned the AR-15 trademark from 1959 to 1974. Legally, the term “AR-15” belongs to Colt.

That’s why other manufacturers use different designations to name their rifles. However, the design is free to be tinkered with in the open domain. Thus, the AR-15 is more of a “platform” than a specific rifle.

Although the AR-15 is legal to own in every US state, a few exceptions exist.

For instance, some states have regulations concerning magazine capacity and feature customizations. In California, for example, one can own a “featureless AR-15 rifle,” or they must register it with the state authorities as an assault weapon if they bought it before 2018.

Moreover, California has prohibited the import, build, and sale of standard “bullet button” AR-15 rifles. Additionally, it’s worth noting that a full-auto AR-15 (M16 version) is considered an assault rifle and is illegal in seven states and Washington DC, including California, Connecticut, Hawaii, Maryland, Massachusetts, New Jersey, and New York.

It’s crucial to check the local laws before purchasing an AR-15, particularly in states known for their strict gun control laws. Gun laws can be confusing and vary from state to state.

For example, a weapon considered fit for squirrel hunting in one state might be considered a “bazooka” in another.

Finally, it’s essential to note that possessing bump stocks is illegal according to the latest rules released by the ATF on March 26, 2019. If you own one, it’s necessary to destroy it or surrender it at your local ATF office. It’s always wise to keep updated with the current laws and regulations concerning the AR-15 to ensure compliance.

Navigating the Different AR-15 Classifications: What You Need to Know

If you’re considering purchasing an AR-15, it’s important to understand the different classifications of this firearm and how they can impact ownership. The AR-15 comes with several legalities and disclaimers, so it’s essential to be well-informed before making any decisions.

According to the Bureau of Alcohol, Tobacco, Firearms, and Explosives (BATFE), a rifle must have a minimum barrel length of 16 inches and an overall length of at least 26 inches. If the barrel length falls short or the overall length doesn’t meet the minimum requirement, then the AR-15 becomes an SBR (Short Barrel Rifle).

A regular AR-15 rifle is a Class II weapon and can only be purchased from a Federal Firearms License (FFL) dealer. Online purchases require shipment to an FFL dealer near you, and you may need to undergo a background check or other formalities, depending on your state’s laws.

An SBR is classified as a Class III weapon, and it must be registered with the ATF under the National Firearms Act (NFA), along with paying a $200 federal tax stamp.

Full auto rifles and handguns are also considered Class III weapons and can only be owned by non-felons and Class III license holders.

Similarly, an AR pistol is classified as a Class III firearm, but it can’t have a stock, only a brace or stabilizer. Additionally, an AR pistol can be converted into a rifle, but not vice versa. Moreover, you can’t add a vertical grip to a pistol.

It’s crucial to note that violating Class III weapon laws is a Class Y felony, which can result in a $100,000 fine, ten years in prison, or both. Therefore, it’s advisable to check with your local laws and ensure that you’re following all regulations before purchasing any AR-15 variant.

For example, SBRs and AR pistols are banned in California, so it’s necessary to check if your state allows you to own them. Additionally, it’s crucial to thoroughly check your local laws regarding building, sale, use, and transportation of the AR-15 and its variants to avoid any legal troubles.

Lastly, it’s worth noting that you must be at least 18 years old to purchase an AR-15 from a licensed dealer. It’s always wise to stay informed and up-to-date with the latest laws and regulations to ensure compliance.

Purchasing an AR-15: What You Need to Consider

If you’re in the market for an AR-15, one of the options you may consider is buying a pre-built rifle that’s already fully assembled and ready to go. There are several reasons why someone might prefer this option over building their own AR-15.

Pros:

1. Ease of Purchase: One of the main advantages of buying a pre-built AR-15 is the ease of purchase. Instead of sourcing all the individual parts and assembling them yourself, you can simply buy a complete rifle and start using it right away.
2. Consistency: Another benefit of buying a pre-built AR-15 is the consistency in quality and performance. With a pre-built rifle, you can be sure that all the components are designed to work together and meet a certain level of quality and reliability.
3. Warranty: Most pre-built AR-15s come with a manufacturer’s warranty, which can give you peace of mind knowing that any defects or issues will be covered by the manufacturer.
4. Cost: While building your own AR-15 can be a more cost-effective option, buying a pre-built rifle can still be cost-effective, especially if you’re looking for a basic model without a lot of customizations. Pre-built rifles can be found at various price points, from affordable to high-end models.

Cons:

1. Limited Customization: One of the drawbacks of buying a pre-built AR-15 is that you’re limited in terms of customization. While some aftermarket parts can still be added or replaced, the overall design and layout of the rifle are already determined.
2. Quality Control: While pre-built rifles are designed to meet certain quality standards, there’s always a risk of getting a defective one. It’s important to research and buy from a reputable manufacturer to avoid any issues.
3. Learning Experience: Building your own AR-15 can be a valuable learning experience, allowing you to understand how the different components work together and how to troubleshoot issues. Buying a pre-built rifle doesn’t offer the same level of hands-on learning.

The price range for pre-built AR-15s can vary greatly depending on the manufacturer, model, and features.

Entry-level models can be found for around $500-$600, while high-end models can cost $2000 or more. Mid-range options typically fall in the $800-$1200 range.

Keep in mind that the price of a pre-built AR-15 is not just about the components themselves but also the manufacturing quality and attention to detail.

Purchasing an 80% DIY Build

Building an AR-15 from an 80% lower receiver is a popular option among gun enthusiasts. This is because it offers more flexibility and customization than pre-built options. However, it’s important to consider a few things before starting an 80% lower build.

Firstly, it’s important to know that 80% lower receivers are not considered firearms by the ATF. This means that you can buy them without registration, background checks, or FFLs. However, it’s worth noting that 80% lowers are banned in some states such as New Jersey, New York, and Washington.

If you buy one in California or Connecticut, it must be engraved with a serial number before completion into a rifle.

An 80% lower receiver looks like a silhouette of an AR lower receiver with no grooves or holes machined into it. To convert it into a firearm, you need a dedicated 80% jig or some home improvement tools. However, keep in mind that 80% lower builds require some level of expertise in gunsmithing and machining.

Building an AR-15 from an 80% lower receiver offers more customization options than pre-built options. You can choose finishes, coatings, and aesthetics. However, the cost of building an 80% lower receiver can be more than purchasing a stripped lower since it requires additional tools and machining.

Furthermore, while it’s not required in most states to serialize or register the finished AR-15, it’s a good idea to do so. This allows for easy tracking of the rifle if it’s lost or stolen.

In summary, building an AR-15 from an 80% lower receiver can be a fun and rewarding experience. However, it’s important to consider the legal requirements and have the necessary skills and tools. It’s also important to keep in mind the cost and time involved in the build, as well as the need for proper serialization and tracking.

Fully Custom DIY AR-15 Builds: Advantages and Considerations

A fully custom DIY build is the most advanced path for building an AR-15. This option provides the highest level of customization, allowing gun enthusiasts to create their own unique masterpiece. However, it requires in-depth knowledge of the AR-15 platform and a willingness to spend time searching for parts and assembling them.

Before embarking on a fully custom DIY build, it’s crucial to determine the intended purpose of the rifle. Will it be used for hunting, home defense, long-range tactical use, or competitions? Each of these purposes requires a rifle with specific characteristics, such as different barrel lengths, enhanced triggers, longer rail space for accessories, and specific calibers.

Custom builds are ideal for those seeking a specific purpose or a unique “tacti-cool” factor. However, if you’re seeking a general-purpose rifle, it’s better to purchase a complete AR-15 rather than building one from scratch.

For gun enthusiasts considering a fully custom DIY build, it’s essential to have the right skills and tools, as well as a clear understanding of the intended purpose and required components. While custom builds may cost less than purchasing a complete rifle, it’s worth noting that upgraded components will typically cost more.

An average build can range from $600 to $1,000, while high-end builds can cost $2,500 or more. A fully custom AR-15 build can be a fulfilling and personalized experience with careful planning and attention to detail.

Bespoke Custom AR-15s: Pros and Cons

If you’re after the highest level of customization for your AR-15, you may want to consider bespoke services offered by some companies. These manufacturers can create a custom rifle tailored to your specific requirements, from simple part-swapping to advanced molding or machining of custom parts.

Now, let’s delve into the advantages and disadvantages of opting for a done-for-you custom AR-15 rifle:

Pros:

1. Finish and Aesthetics: Custom build services offer a unique and personalized rifle to your exact specifications. This is great for individuals who want a distinct rifle with a custom finish and aesthetics to suit their tastes.
2. Saves Time & Tools: Done-for-you AR-15 builds save time and effort. For those who lack the tools, skills, or time to build an AR-15 from scratch, a custom build service is a great option.

Cons:

1. Expensive: Custom AR builds are typically costly, especially if you’re looking for unique features and accessories. This cost increases further if you’re interested in things like melonite or cerakote coated parts, match grade barrels, or featherweight triggers.
2. Compatibility Issues: While rare, some extremely customized builds may face compatibility issues with general replacement or aftermarket AR upgrades. This can be a major inconvenience for those looking to upgrade or modify their rifle in the future.

Alternative AR Calibers: A Brief Overview

The AR-15 platform is highly versatile and can be chambered in several calibers in addition to the commonly used .223 and 5.56 NATO rounds. Some noteworthy calibers include the 9mm, .300 Blackout, 6.5 Creedmoor, .308 Winchester (also used in the AR-10), 6.8 SPC, .50 Beowulf, .338 Federal, .450 Bushmaster, and 7.62x39mm.

Here is a list of the calibers available. 

.22LR	.410 Shotgun
.22 PPC	.45 ACP
.22 Nosler	.450 Bushmaster
.224 Valkyrie	.458 SOCOM
.223 Winchester Magnum	.50 Action Express
.243 Winchester Magnum	.50 Beowulf
.25 Winchester Magnum	5.45×39mm
.25-45 Sharps	5.56x45mm/.223
.277 Wolverine	FN 5.7×28mm
.30 Carbine	6.5mm Grendel
.30 Remington AR	6.8mm Remington SPC
300 AAC Blackout	7.62×37mm Mustang
300 OSSM	7.62x39mm
375 SOCOM	9mm (AR9)
7.92x33mm Kurz	10mm Auto
.40 S&W

Additional Calibers

Here are a few less common calibers you can chamber an AR 15 in.

Each of these calibers offers unique advantages depending on the intended use, whether it be long-range shooting, hunting, tactical purposes, or home defense. Here is a brief overview of what many consider to be the main alternative AR caliber builds.

AR9 (9mm)

The AR9, also referred to as the 9mm AR, was created in 1982 under the name Colt 9mm SMG with the goal of developing a shorter AR platform that fired a pistol caliber.

The main benefit of the AR9 is its blowback operation, which is an excellent choice due to the smaller size of the 9mm round and the limited gas produced.

AR9s are widely used in USPSA competition and home defense due to their ease of use and control. They are available in both carbine and pistol configurations, and compatible with both Colt-style and Glock 9mm magazines, making them easily accessible to a broad range of users.

Pro’s:

1. Lightweight and low recoil firearm for short-range shooting
2. Ease of use and control
3. Glock magazine compatibility
4. Blowback operation ideal for smaller 9mm round

Con’s:

1. Less powerful than some of the other calibers used in the AR platform
2. Limited aftermarket support for parts and accessories
3. May not be suitable for long-range shooting or hunting

Investing in a complete 9mm AR upper is highly recommended since the bolt, operating mechanism, and muzzle threads are entirely different from those of a 5.56. However, it is essential to note that not every kit will offer LRBHO (last round bolt hold open) capability.

The AR9’s Glock magazine compatibility and compact size make it an attractive option for home defense and competition shooting. However, it’s crucial to consider the limitations of the 9mm round and the specific needs of the shooter.

Nonetheless, the AR9 can be an excellent option for those seeking a lightweight, easy-to-use firearm for short-range shooting.

.300 AAC Blackout

The .300 AAC Blackout, also known as .300 BLK, is an intermediate cartridge developed by Advanced Armament Corporation in 2009. The cartridge was created to provide extra power in the M4 rifle without changing much of its design.

The .300 BLK uses a .30 caliber projectile (.308 inches) and was developed by fattening out the 5.56 case and shortening it a bit, resulting in a case that could hold more powder and fire a heavier bullet at the same pressure as the 5.56. The .300 BLK has its design inspired by the .300 Whisper, a cartridge developed by Wildcat Industries for use with suppressors.

Due to this connection, the .300 BLK has some impressive performance traits with suppressors. The cartridge was specifically designed to make the M4 a short and compact rifle with heavy punching power, making it an ideal choice for special forces.

Pro’s:

1. Highly adaptable cartridge for a variety of shooting situations
2. Excellent stopping power for hunting and tactical applications
3. Available in a variety of bullet weights
4. Can be used in short-barreled rifles and suppressed firearms
5. Can instantly convert an M4 or AR-15 chambered in 5.56 into a .300 BLK with a simple upper receiver or barrel change

Con’s:

1. Heavier recoil and more ammo weight due to bulkier bullet
2. Can be more expensive than some other AR-15 calibers
3. May not be suitable for long-range shooting

One of the most significant advantages of the .300 BLK is its versatility. The cartridge is available in a variety of bullet weights, including 78 grain, 90 grain, 110 grain, 125 grain, and 220 grain.

While the bulkier bullet translates to heavier recoil and more ammo weight, the fact that an M4 or AR-15 chambered in 5.56 can be instantly converted into a .300 BLK with the simple change of the upper receiver or barrel makes it a great solution.

The .300 BLK offers excellent stopping power and is ideal for hunting and tactical applications, especially when used in short-barreled rifles and suppressed firearms. However, it may not be the best choice for those on a tight budget or those who require a caliber with less recoil.

It’s crucial to choose the appropriate ammunition and barrel length for maximum effectiveness, with a barrel length of 10-16 inches typically recommended for the .300 BLK. 

7.62 x 39mm

The 7.62×39 mm is a popular intermediate cartridge that has undergone several modifications since its introduction in 1943. The round features a .300 inch diameter bullet, or what is referred to as .30 cal in the United States.

Its design was focused on creating an affordable and reliable round for self-loading rifles, with a highly tapered case that gives the cartridge a unique shape and is responsible for the banana-shape of AK magazines.

One of the most interesting features of the 7.62×39 mm is that it was designed to work best with steel cases rather than traditional brass ones, cutting costs and increasing mass production.

Many AK enthusiasts argue that the 7.62 Russian works best in steel cases. The round was originally designed with Berdan primers, the insignia of cartridges manufactured in the former Soviet Union. However, as the cartridge became popular worldwide, the Boxer primer was introduced in the United States to ease reloading and provide reliable burning, leaving a cleaner chamber.

While the 7.62×39 mm is not the same as .308, it can be seen as the closest relative to the .30-30 Winchester in terms of design, shape, and weight. It’s important to note that the .308 bullet is an acronym for 7.62×51 mm rounds in the United States, which are longer and better suited for longer range rifles and shots.

Here are the pro’s and con’s of the 7.62×39 mm cartridge:

Pro’s:

1. Affordable and widely available
2. Reliable and rugged design
3. Works well in steel cases
4. Good balance of stopping power and controllability
5. Suitable for hunting and recreational shooting

Con’s:

1. Limited effective range
2. Inconsistent accuracy at long ranges
3. Recoil can be significant in smaller firearms
4. Mil-surp ammo requires dedicated cleaning after every shooting session

Many people prefer to purchase the 7.62×39 mm rounds due to their cheap availability, especially when it comes to military surplus ammo, which can be found for as low as $100 for 1000 rounds in some sales. However, users should keep in mind that dedicated cleaning is required after every shooting session with mil-surp ammo.

Overall, the 7.62×39 mm cartridge remains a popular choice among shooters for its affordability and reliability.

224 Valkyrie

The 224 Valkyrie cartridge is one of the top-performing cartridges when it comes to long-range shooting. It was developed to handle heavier 0.224” diameter bullets, which the 5.56 NATO cartridge cannot handle effectively.

One of the limitations of the 5.56 NATO cartridge is that the longest bullet that can be seated to proper magazine length is 77 grains. This works well for medium-range shots but if you want to shoot longer distances, a heavier bullet such as the 90 grain Sierra Matchking (SMK) would be ideal.

Federal Premium Ammunition noticed the popularity of the 22 Nosler cartridge and decided to create a cartridge that could compete with it. They went back to the ballistics lab and designed the 224 Valkyrie cartridge.

Unlike the 22 Nosler, which uses a proprietary case design, the 224 Valkyrie uses a necked down 6.8 SPC case to accept a 0.224” diameter bullet. This configuration allows for the use of the 90 gr SMK in a standard 6.8 SPC magazine. Federal released the 224 Valkyrie at SHOT Show 2018, featuring a 90 gr SMK with a high BC of 0.563.

This high BC makes it possible for the 224 Valkyrie to shoot up to 1,300 yards, providing long-range shooters with a low-recoiling, cost-effective cartridge that can achieve sub-MOA accuracy.

Pros:

1. Can handle heavier 0.224” diameter bullets for long-range shooting
2. Affordable and widely available
3. Offers sub-MOA accuracy
4. Allows shooters to shoot up to 1,300 yards

Cons:

1. Not ideal for short-range shooting
2. Requires a specialized magazine

If you enjoy long-range target shooting and want to stick with a 22-caliber bullet, the 224 Valkyrie is an excellent choice, offering a combination of power, accuracy, and affordability that is hard to beat.

6.5 Grendel

The 6.5 Grendel cartridge is a popular choice for long-range shooting with the AR-15 platform. It uses a 6.5mm bullet that has a high ballistic coefficient, giving it a flat trajectory and making it ideal for long-range target shooting.

While it took some time for the 6.5mm bullet to become popular in North America, it has since gained a reputation for its effectiveness at long range. Its sleek and aerodynamic design allows for high speed and low drag, making it an excellent choice for long-range accuracy.

Developed in 2003 by Alexander Arms, the 6.5 Grendel was designed to extend the effective range of the AR-15 beyond 800 yards.

By using the same high ballistic coefficient 0.264” diameter bullets as the 6.5 Creedmoor, the 6.5 Grendel can maintain sub-MOA accuracy and supersonic velocities out to 1,200 yards with less recoil than the 308 Winchester.

Pro’s:

1. High ballistic coefficient for flat trajectory and long-range accuracy
2. Supersonic velocities out to 1,200 yards
3. Half the recoil of the 308 Winchester
4. Maintains sub-MOA accuracy

Con’s:

1. Limited availability compared to more popular cartridges
2. Limited availability of rifles chambered in 6.5 Grendel

6.8SPC

The 6.8 Special Purpose Cartridge (SPC) was developed as a joint project between Remington Arms, the US Special Operations Command (USCOCOM), and the U.S. Army Marksmanship unit in 2004.

This unique cartridge was designed to enhance the terminal performance of the M4 carbine for indoor combat and provide exceptional short-range ballistics.

While the goal of the 6.8 SPC program was to mimic the stopping power of the 7.62x39mm Soviet round, the round did not get approval for combat use by the armed forces due to chamber design issues.

Nevertheless, this doesn’t make it an ineffective cartridge. In fact, the 6.8 SPC is an incredibly deadly short-range round, delivering a 45% increase in kinetic energy compared to the standard 62-grain 5.56 NATO round.

The 6.8 SPC has proven itself to be an ideal choice for home defense, offering superior stopping power at close ranges. It is also a popular choice for deer and hog hunting for shots under 200 yards.

Pro’s:

1. Exceptional short-range ballistics
2. Increased kinetic energy for superior stopping power
3. Ideal for home defense and hunting under 200 yards

Con’s:

1. Not suitable for long-range shooting
2. Limited availability of rifles and ammunition

Overall, the 6.8 SPC is a formidable cartridge that offers excellent performance in specific situations.

When used in a home defense or short-range hunting scenario, the 6.8 SPC is sure to deliver the necessary stopping power. However, for those seeking a long-range cartridge, the 6.8 SPC may not be the best option.

AR Pistol

The AR pistol is a shortened version of the AR-15 rifle, with a barrel length of under 16 inches and an overall length of no more than 26 inches (excluding muzzle devices). However, owning one requires filling out some legal paperwork and paying a $200 tax stamp to the NFA.

In contrast to the AR-15 rifle, AR pistols are not allowed to have stocks or vertical foregrips, but stabilizing braces can be used in place of stocks. These braces can be uncomfortable to shoot from the shoulder and require the use of a forearm strap for stability.

The primary advantage of an AR pistol is its compact and concealable design, and the lack of a stock makes it less deadly than a traditional rifle. However, it’s crucial to verify local state laws regarding the classification of AR pistols to ensure compliance with regulations.

The AR pistol is commonly available in three calibers – 9mm, .223, and .300 BLK – with the .300 BLK being a standout option due to its excellent performance in an AR pistol platform.

The most frequent barrel length for an AR pistol is 9 inches, particularly for .300 BLK, but personal preference may dictate a longer or shorter barrel.

Pro’s:

1. Compact and concealable design
2. Less deadly than a traditional rifle due to lack of stock
3. Available in a variety of calibers
4. Excellent performance in .300 BLK caliber

Con’s:

1. Requires legal paperwork and a $200 tax stamp to the NFA
2. Cannot have stocks or vertical foregrips
3. Brace may be uncomfortable to shoot from the shoulder
4. State laws regarding classification of AR pistols can vary widely

When choosing an AR pistol, it’s important to take into account the particular use case and intended purpose, as well as legal requirements and personal preferences regarding caliber and barrel length.

Best AR-15 Rifle Brands

When searching for an AR-15 rifle, there is an overwhelming number of brands and models to sift through, ranging from established brands with a track record of excellence to newer, trendy brands that incorporate innovative features. To simplify your search, this guide will showcase some of the top AR-15 rifle brands available on the market today.

There are more than 40 brands that manufacture AR-15’s. This is a short list of the dozen brands we think you should pay attention to.

	Sig Sauer provides an array of AR-15’s, as well as pistols, magazines, ammo, and suppressors. They are one of the most respected brands on the market, and were adopted as the main sidearm of the US Army. They are known for making polymer framed guns. They are one of the brands that build custom AR-15’s for customers. They have a pretty advanced design studio on their website.
	Barrett, the renowned company behind the famous .50 anti-material rifle, also produces an exceptional AR-15. Although they may not come cheap, their rifles are truly remarkable. The Barrett M82A1 is a globally recognized and iconic rifle, and it has been the preferred choice for military and law enforcement agencies as an anti-materiel rifle since 1989. Additionally, the Barrett MRAD offers a versatile option to adapt to specific mission profiles, providing the user with choice and flexibility.
	LMT is a top-tier AR-15 brand, with the Mars-L receiver being the best lower receiver on the market. The monolithic upper receiver facilitates quick barrel changes on the LMT monolithic rail platform. The upper receiver is milled from a single piece of aluminum, resulting in no seams or welding, and no gaps in the rail. Because of this, you can expect to pay a higher cost, but it’s a high quality rifle.
	Knights Armament is a top-tier AR-15 brand and their SR-15 is well known in the high-end market. It has a forged aluminum lower receiver with an ambidextrous magazine release, and some proprietary features on the upper including the bolt, gas system, and barrel, making it stand out in terms of durability and reliability. Expect to pay a pretty penny for one of these.
	Heckler & Koch manufactures some of the most high-quality and sophisticated handguns, assault rifles, training systems, grenade launchers, and precision rifles in the world. Their products are used by the US Army and the Navy SEALs. The HK MP5 is the most successful and popular 9mm submachine gun ever invented, though the HK USP is their most well known gun today.
	LaRue is another major player in the AR-15 market, providing a wide range of parts and accessories for these rifles. They make rifles, uppers, barrels, triggers, and targets. They are a trusted supplier for the military, and the brand is widely regarded as the gold standard in direct impingement AR-15’s. Although their stuff can be quite pricey, it is covered by a lifetime warranty.
	Smith & Wesson is well known for their handguns, but they also make some affordable AR-15’s, namely the M&P Sport 15. They provide decent customer support and a solid warranty plan. These are a great option for anybody on a budget or looking for a starter AR.
	Colt is the official owner of the trademark “AR-15,” and is considered an excellent choice for those who want a reliable and affordable AR. The Colt LE6920 is considered the closest you can get to the military’s M4 rifle. Colt’s AR’s are known for their durability and toughness, making them ideal for harsh environments. You can usually pick one up for less than $1,000.
	BCM offers several top quality AR-15 rifles, including an array of CQB. They use an enhanced trigger, which provides a smooth and consistent pull for improved accuracy. The rifles come with some high quality “furniture,” including stocks, grips, and handguards. They also developed the BCMGunfighter charging handle which features a stronger tactical latch system.
	PSA is a top choice for AR-15 rifles. The PA-15 line is their take on the AR-15 platform, and is available in a number of configurations. They sell complete firearms, but are a great source for components like uppers, barrels, and handguards. Their prices are affordable and their extensive inventory of aftermarket parts make them a great option for both building and buying ARs.
	Daniel Defense is a huge government contractor and their rifles are loved by veterans and LEO’s alike. Their prices can range between $1,000 – $1,800, but their DDM4 V7 model is extremely popular among AR enthusiasts. It features a 16-inch cold hammer-forged barrel, M-LOK handguard, and ambidextrous controls. DD sources raw materials locally, meaning their rifles are truly made in the USA.
	Springfield Armory is a respected firearms manufacturer with a long history of supplying firearms to the US military and law enforcement. The SA Saint is a popular and reliable AR-15 rifle with a free-floating handguard and the Accu-Tite tension system. The XD-M series of pistols is also noteworthy, offering versatility and reliability with features like a match-grade barrel and adjustable sights. Most SA AR’s will cost about $1,000.

Remember, you get what you pay for. 

Top tier AR’s can range from $1,200 to $2,000. You can get a decent mid-tier option for around $900. There are also some budget AR’s for $550ish if you don’t need all of the bells and whistles. 

Best AR-15 Parts & Accessories Brands

While out-of-the-box AR’s are typically ready to go, there are many upgrades and add-ons to consider. These brands offer parts and accessories designed to improve the user experience. Ergonomics, speed and efficiency, accuracy, special-use situations, and reduced load are some of the reasons people shop for these products.  Additionally, some of these brands both manufacture and distribute firearms products.

	Magpul is a highly respected brand in the firearms industry, known for their innovative and high-quality accessories. Their PMAG magazine has become a favorite among AR-15 owners, while their MOE line of products offer ergonomic and affordable upgrades to rifles. They also make stocks, grips, and other accessories that are popular among gun enthusiasts.
	Geissele is a top-tier brand when it comes to high-quality triggers for AR-15’s. Their triggers are known for being extremely reliable and crisp, making them a favorite among competitive shooters and military personnel. They also offer other accessories such as handguards, rails, and optic mounts.
	Streamlight is a well-known brand in the tactical flashlight industry, providing high-quality and durable flashlights for law enforcement and military personnel. Their lights are also popular among gun owners, offering a bright and reliable source of illumination in low light conditions.
	Aero Precision is a manufacturer of high-quality AR-15 receivers, uppers, and lowers. They also offer other parts and accessories for the AR-15 platform, including handguards and charging handles. Their products are known for their quality and affordability.
	Leapers UTG is a brand that offers a wide range of affordable accessories for AR-15’s and other firearms. Their products include scopes, rails, and other tactical gear, all designed to provide value to the customer without breaking the bank.
	Viking Tactics, founded by former Special Operations soldier Kyle Lamb, provides a wide range of tactical gear including slings, belts, and other accessories. Their products are designed with the needs of military and law enforcement personnel in mind, but are also popular among civilian gun owners.
	Midwest Industries provides high-quality accessories for firearms, including handguards, rails, and optic mounts. Their products are known for their durability and reliability, making them a favorite among gun enthusiasts.
	Timney Triggers is a company that specializes in producing high-quality triggers for firearms. Their AR-15 triggers are known for their precision and reliability, making them a popular choice among competitive shooters and gun enthusiasts.
	Wilson Combat is a high-end firearms manufacturer, known for producing some of the finest custom 1911 pistols in the world. They also offer high-quality AR-15’s and other firearms, all designed with precision and attention to detail.
	Brownells is a company that offers a wide range of firearms, parts, and accessories. They are known for their extensive inventory of gun parts, as well as their own line of products designed to provide value and quality to customers.
	Leupold is a respected brand in the optics industry that offers top-quality and dependable scopes for hunting, shooting, and tactical purposes. Their scopes are widely favored for their accuracy and resilience, making them a preferred choice among outdoor enthusiasts and seasoned shooters alike.
	Holosun is a brand that offers a range of red dot sights, designed for use on firearms such as the AR-15. Their sights are known for being affordable and reliable, providing a great value for those in need of a good optic.

This is not a comprehensive list, but they are some of the most popular brands on the market.

AR-15 Attachments and Customizations

After purchasing an AR-15 from the original equipment manufacturer, there are many components that can be replaced or customized.

The trigger, handguard, stock, grip, charging handle, muzzle device, sights/optics, and magazine are among the most commonly altered parts. In addition, users may opt to change the upper or lower receiver, barrel, bolt carrier group, or gas system for performance or aesthetic purposes. The variety of customization options available for AR-15’s is a major draw for gun enthusiasts.

Triggers

Customization possibilities for the AR-15 trigger are abundant, and shooters can tailor their triggers to fit their needs. Competitive and tactical shooters often prefer a refined trigger with a light pull weight when they have the time to relax and take an accurate shot, or when speed and precision are crucial. Factors like creep, overtravel, after travel, and pull weight all play a role in trigger performance.

The AR-15 factory trigger typically requires a pull weight of four to seven pounds, while military M4 rifles use a heavier trigger pull weight of five to nine pounds. This heavier weight helps prevent negligent discharges under stressful situations. However, aftermarket customization can modify the AR-15 trigger pull weight to a minimum of 1.5 pounds, using triggers like the Timney Calvin Elite, although they are expensive.

Aftermarket triggers for the AR-15 come in drop-in or standard configurations. Drop-in triggers are plug-and-play and housed in a metal housing, while standard triggers require manual assembly, which can be time-consuming. Aftermarket triggers may have a set pull weight or be adjustable, and adjustments can be made using screws or by replacing trigger springs with preset pull weights.

Triggers for the AR-15 are always semi-automatic, as full-auto triggers are not legally allowed unless you own a pre-ban M16 automatic weapon. There are also different trigger mechanisms, such as single-stage triggers that break and fire in one pull, double-stage triggers that require a heavy first-stage break followed by a lighter second-stage break, and binary triggers that release two shots with a single pull and release.

Two-stage triggers are more popular with competitive shooters, as the lighter second stage allows for greater accuracy with minimal movement and effort.

Finally, trigger guards can also be modified for added comfort, especially for shooters with oversized or small palms. Additionally, an oversized trigger guard can be helpful when working with thick gloves in winter conditions.

Handguards

The AR-15 rifle was originally developed as the Armalite rifle in the 1950s, and its earliest version used by the U.S. Defense Forces featured a triangular A1 handguard at the front. The AR-7 rifle, a predecessor to the AR-15, lacked a handguard and was used by the Airforce as a survival rifle for pilots.

Handguards are essential accessories for AR-15 rifles as they offer a better grip and protect the shooter’s hands from the hot barrel. Over time, AR handguards have undergone significant improvements, and designs like the M-LOK and KeyMod attachment systems have transformed handguards into platforms for mounting other accessories.

AR-15 handguards are categorized into two types: drop-in and free float. Drop-in handguards come in two pieces and can be installed or removed easily by pulling back the spring-loaded “delta ring.” Although they are easy to install, these handguards come in contact with the barrel and can affect accuracy due to barrel harmonics. These handguards are affordable and limited in length by the AR’s gas system.

In contrast, free float handguards are mounted directly to the upper receiver and do not touch the barrel, resulting in better accuracy, especially when using bipods or resting the rifle on an improvised platform. A low profile gas block can be used to increase the length of the handguard and provide additional accessory mounting options.

Handguards can have picatinny rails on one or more sides for attaching accessories, while those with M-LOK or KeyMod design systems offer additional flexibility with compatible mounting couplers. Free float handguards come in a variety of designs, including carbon fiber and skeletonized designs that reduce overall weight. Longer handguards are ideal for competitive and tactical use.

Stocks

Another great way to customize your AR is with the stock. Picking the right stock can have a tremendous impact on comfortability, accuracy, and ease of use. Two of the most common materials for AR-15 stocks are polymer and aluminum, with each having its own pros and cons. While polymer stocks are lightweight and affordable, aluminum stocks offer greater durability and may be a better option for heavy use.

Also consider the length of pull. This is the distance from the trigger to the butt of the stock and can vary based on the shooter’s size and preference. Some stocks come with adjustable length of pull, while others are fixed. Some stocks can be quickly adjusted when changing from a patrol to active position. 

Additionally, some stocks have compartments, built-in sling attachments or adjustable cheek risers. 

Some of the different types are fixed, collapsible, adjustable, minimalist, PDW, and folding stocks. Each has their own advantages and disadvantages. 

Fixed stocks are the classic M16-style stocks with little to no adjustment options, but some may include small compartments for carrying essential items. They are a good option if you’re looking for a basic and durable stock.

Collapsible or telescoping stocks can be adjusted to increase the length of pull, making them a great option if you need to adjust the length of your stock for comfort or if you’re wearing additional gear. However, in some states, collapsible stocks may be illegal.

Adjustable stocks can be adjusted in multiple ways, including the butt pad length and cheek risers. They are usually fixed stocks that provide a great fit for multiple users.

Minimalist stocks are designed to be extremely lightweight and compact, making them a great option for long-distance carrying or tactical situations. They may be either fixed or collapsible, but they have a low profile.

PDW stocks are designed for compactness and durability, making them ideal for close-quarters battle (CQB) situations. They are usually more compact and durable than standard polymer stocks and may include their buffer system.

Folding stocks allow you to fold your rifle for easier transport or storage. However, you must be aware of the laws regarding folding stocks in your state, as some states may consider a folded rifle to be a short-barreled rifle (SBR).

It’s important to keep in mind that there may be legal regulations on certain types of stocks in your area, such as collapsible or folding stocks. Make sure to research and understand these regulations before making a purchase.

Grips/Handstops

AR-15 rifles come with a standard pistol grip which is easy to hold and helps in proper weight distribution. However, grips are one of the most customizable parts of an AR-15, and there are a variety of options available to shooters. Some grips feature molded grooves for better finger grip, while others may have an overmolded swell to fit larger palms. Texture and material can also vary, with some offering a more stable grip than others.

When choosing a grip, it is important to consider the intended use of the rifle. For stationary situations like benchrest shooting or hunting, any style of grip will do. However, for defense or competition shooting that involves maneuvering, choosing the right grip becomes essential. It is worth noting that some states have restricted laws, such as California, which require featureless grips on AR-15s.

In addition to grips, foregrips are also a popular accessory for AR-15 rifles. A vertical foregrip can provide better stability and gripping options, particularly for defense forces and competition shooters. Foregrip designs can range from simple to complex, with some models even splitting to form a small bipod, while others may feature integral accessories like flashlights. However, it is important to note that vertical foregrips are restricted in some states and can only be mounted on AR-15 rifles with a minimum overall length of 26 inches.

If a vertical foregrip is not an option, a handstop can be used as an alternative. A handstop works as a clutch to allow the shooter to rest their fingers on the handguard while providing added stability.

For hunters or long-range shooters, a bipod can be a valuable addition to an AR-15. A bipod is a two-legged device mounted under the handguard of the rifle to provide a stable shooting platform, mainly in the prone position. While bipods with adjustable height, pan, and can’t provide versatility, simpler non-adjustable designs may suffice for certain uses.

It is important to consider the intended use of the rifle when selecting grips, foregrips, and bipods, and to abide by state laws and regulations.

Rails/Riser Mounts

Customizability is one of the key features that make the AR-15 rifle so popular among firearm enthusiasts. A major component that plays a crucial role in this customizability is the rail system. The MIL-STD 1913 rail, also known as the Picatinny Rail, is a standard rail system found on the top receiver or the handguard of the rifle. However, there are also two other modular mounting systems that can be used to top the Picatinny rail: the M-LOK and the KeyMod.

The M-LOK is a free license mounting system designed by Magpul. The KeyMod, on the other hand, is a newer system introduced in 2012 by Eric Kinsel, an employee of VLTOR Weapon Systems at the time. Both the M-LOK and KeyMod mounting systems offer users the flexibility to mount rails over them, allowing them to decide on the position and length of the rail to be attached. This can help reduce unnecessary weight and space.

When it comes to choosing between M-LOK and KeyMod, personal preference plays a big role. However, according to tests conducted by the United States Special Operations Command (USSOCOM), the M-LOK is twice as strong as KeyMod, making it the preferred choice for military applications.

In addition to rail systems, rail-based accessories are also popular for customizing the AR-15. One such accessory is the riser mount, which is a short Picatinny rail with a riser on the base. The riser elevates the position of the rail higher, allowing users to position optics at a higher level for optimal compatibility with the cheek weld position.

Riser mounts come in different types, including low profile, medium profile, and high profile, which vary in height and usage. It is important to select the right riser mount height to match the user’s optics and rifle configuration for optimal shooting experience.

In addition to riser mounts, rail systems can be used to mount a variety of other accessories, such as lights, lasers, bipods, and grips, among others. This allows users to customize their AR-15 to meet their specific needs and preferences. With so many options available, the AR-15 truly lives up to its reputation as one of the most customizable firearms on the market.

Charging Handle

The charging handle, also known as the cocking handle or bolt handle, is an important component of the AR-15 rifle. Located inside the upper part of the receiver, the charging handle allows the shooter to pull back the bolt and set it into the ready/cocked position.

In addition to preparing the rifle for firing, the charging handle has several other functions. It can be used to eject spent or misfired rounds, clear jams or misfeeds, and release the LRBHO.

Aftermarket charging handles are available in a wide range of designs, with some specifically aimed at solving particular problems. Some handles have extended latches for easy grip, while others are extended on both sides for ambidextrous use.

If you prefer a side-charging AR, you’ll need to purchase a side-charging handle, as the AR-15 has a top charging handle. Finish options, such as nitride, can impact the handle’s lubricity and durability, while ergonomic designs and grooves can provide easy and comfortable grips.

For tactical and defense applications or competitions, high-end and ambidextrous handles are often preferred. These unique designs include latches that make it easier for left-handed users to operate a right-handed AR.

It’s important to note that the charging handle you choose should be based on your specific needs and preferences. For example, a handle with an extended latch might be great for ease of use, but it could snag on gear or clothing. And while a smooth, easy-to-operate handle is ideal for quick follow-up shots, it might not be the best choice for precision shooting. Ultimately, the charging handle you select should work well with your overall shooting style and preferences.

Gas System/Buffer Mods

When it comes to the gas system of an AR-15, it’s a crucial component that controls the recoil and ensures proper bolt cycling. However, many off-the-shelf AR-15s have an overgassed system, which results in more gas being directed back to the bolt than needed. This can cause unnecessary pressure, wear on the action components, and more recoil.

One way to check the gas system of your AR-15 is by using an adjustable gas block that lets you increase or decrease the amount of gas flow to fine-tune the rifle according to your specific setup, such as the ammo you’re using and the weight of your BCG and buffer. Competitive and long-range shooters usually opt for adjustable gas blocks on their high-end rifles.

The buffer weight is another important factor to consider as it determines how much recoil the shooter will feel. It’s crucial to choose the appropriate buffer weight that’s relative to the gas system length. For instance, using a heavy buffer on a short gas system or a light buffer on a long gas system can cause issues.

There are different types of buffers available for AR-15s, such as carbine, H1, H2, H3, and 9mm buffers. The type of buffer you choose will depend on your specific setup, such as barrel length, gas system length, and the type of ammunition you’re using. 

For example, a carbine buffer is a component in the buffer system of an AR-15 rifle that helps to regulate the recoil of the weapon. It is specifically designed for use with rifles that have a shorter gas system and lighter bolt carrier group (BCG). The carbine buffer is shorter and lighter than a standard buffer, allowing for faster cycling of the weapon and reducing felt recoil. It also helps to prevent the bolt from opening too early or too late, ensuring proper cycling and reducing wear and tear on the rifle’s internal components.

The use of a carbine buffer is especially important for those who use their AR-15 for close-quarters combat, where fast cycling and reduced recoil are essential.

Another factor to consider is the buffer spring, which can also impact the smoothness of the recoil. Hotter ammunition can generate more blowback, so it’s important to choose the right buffer spring for your specific setup.

By considering these factors and choosing the appropriate gas system, buffer weight, and buffer spring, you can optimize the performance of your AR-15, reduce recoil, and increase accuracy.

Sights/Optics

Sights and optics is one of the aspects of AR-15 rifles that can be highly customized. A number of accessories, such as sights, scopes, lasers, and flashlights can enhance an operator’s performance for specific applications. Each accessory has its own advantages and disadvantages for different purposes.

Sights: Iron sights or BUIS can serve as a backup when optics fail, but they have limited use for serious applications. They are best suited for non-serious purposes, such as for plinking and range use. However, they are still essential and reliable for when you need a backup. 

Scopes: Scopes can range from small red dot sights to high variable zoom scopes for medium and long-distance shooting. The type of scope you choose should depend on your intended application. If you have the budget and desire to use advanced optics, you can consider the best AR-15 night vision scopes and thermal scopes for hunting in the dark. However, scopes can be heavy and bulky, and may not be suitable for close quarters combat or quick target acquisition.

Lasers: Lasers are useful for tactical applications such as home defense or combat. They allow for quick target acquisition in dark situations and are very effective for aiming and shooting. However, they are not suitable for long distance shooting and may be difficult to see in bright daylight conditions. Additionally, the use of a laser can give away your position to an enemy.

Flashlights: Flashlights can be used for illuminating your target area and make aiming easier in low-light conditions. They are also versatile and can be mounted or used handheld. However, the use of a flashlight can give away your position to an enemy, and can be less effective in bright daylight conditions.

Laser and flashlight combo options are available on the market, which provide the advantages of both accessories. These combo setups are highly effective for tactical applications, but can be heavy and bulky.

Barrels & Muzzle Devices

When buying an AR-15 rifle, the barrel is a critical component to consider, and it’s available in a variety of options. There are three types of barrel profiles – light, medium, and heavy – each with its specific benefits. Barrel length is also an important factor to consider, with 16-18 inch barrels ideal for general use, and different lengths required for hunting, competitions, and long-range shooting.

To enhance barrel performance, modifications like exterior coating, inner lining, fluting, rifling, twist rate, and profile can be made. For home defense, shorter barrels are preferred, and compact SBR or AR pistols are the best options. However, owning an SBR requires registration with the ATF.

For hunting, 18-20 inch barrels are optimal, as they provide a good mix of accuracy and velocity, while barrels longer than 20 inches, like the 24-inch heavy bull profile barrel, are preferred for long-range and precision shooting. A bull profile barrel is cylindrical and stiffer, making it more resilient to changes in barrel harmonics.

When buying an AR-15 rifle, a flash hider typically comes as standard. Some popular attachments to consider include:

Muzzle Brakes: reduce felt recoil and improve control, by diverting the muzzle blast to the side or in a radial pattern.

Compensators: reduce muzzle climb and provide greater control over the muzzle, by diverting the muzzle blast and gasses upward when the rifle is fired.

Flash Suppressors: quickly disperse gas to reduce the signature flash when firing. These devices are also known as flash hiders, but are banned in California, Massachusetts, and New York.

There are also hybrid brakes that perform both functions. Suppressor use is subject to legal restrictions and registration, and it’s critical to confirm local laws before purchasing.

It’s advisable to choose a threaded muzzle barrel with a target crown to increase accuracy. To make an informed purchase decision, it’s essential to understand the benefits and limitations of each barrel and attachment option available for AR-15 rifles.

Magazines

One of the integral parts of the AR-15 rifle is the magazine, which plays a vital role in ensuring a smooth and uninterrupted shooting experience. Magazines can be made of either metal or polymer, and both types have their pros and cons. Metal mags are more durable but heavier, while polymer mags are lighter and less expensive. Some hybrid mags combine metal and polymer for a balance of strength and weight.

When choosing a magazine, it’s important to ensure that it has a good anti-tilt follower and a strong spring to ensure reliable feeding. It’s also essential to use dedicated mags for each caliber, even if they are interchangeable.

Magazine couplers are a useful accessory that can be used to combine two or more magazines together for quick changing. They’re especially useful for combat, self-defense, and competitions where time is critical. However, couplers add weight to the front of the AR-15, so it’s important to keep your forearms strong. Also, not all couplers are compatible with all magazines, so be sure to check beforehand.

Speedloaders are also an essential accessory that can save you time and effort when reloading magazines. They come in a variety of designs, from pocket-sized ones to larger ones with higher capacity and quicker operation. Speedloaders are particularly helpful during magdump range sessions or when you have to fill up a lot of mags at once. They can also be helpful for people with finger arthritis or other issues that make reloading magazines difficult.

Overall, selecting the right magazines, couplers, and speedloaders for your AR-15 setup is important for ensuring reliable feeding and efficient reloading.

Ammunition

However, when choosing ammunition for your AR-15, it’s important to understand the difference between 5.56 and .223 Remington.

Although both cartridges and bullets have the same dimensions, the .223 Rem is a civilian round loaded to lighter pressures than the 5.56, which is a military round. While it is possible to shoot a 5.56 from a .223 Rem barrel, doing so could damage your barrel or even result in a severe explosion accident.

On the other hand, a 5.56 round can be fired safely from a rifle chambered in .223 Wylde. It’s all about SAAMI approved pressures.

When it comes to choosing the right bullet type for your AR-15, you’ll generally have three options to choose from: hollow point, soft point, and FMJ (Full Metal Jacket).

Hollow point rounds are preferred for hunting as they expand quickly upon impact, transferring their energy instantly.

Soft point bullets, on the other hand, offer better penetration than a hollow point and also provide good expansion, making them a good choice for big game.

FMJ bullets, which are used by the military, are intended to wound rather than kill. While they are mostly used for range use or competitions with AR-15 rifles, they are illegal for hunting due to their heavy penetration and may not be the best choice in an urban home defense scenario.

In addition to the bullet’s type, there are other factors to consider when selecting ammunition for your AR-15. Grain weight is one important factor, as different grain weights can impact accuracy, velocity, and terminal ballistics.

Additionally, twist rate, which affects the stabilization of a bullet in flight, can also significantly impact accuracy. Understanding your barrel’s twist rate and how it affects the performance of your chosen ammunition is crucial to optimizing your rifle’s accuracy.

While steel-cased ammunition is often less expensive than brass-cased ammunition, it may also be less reliable and cause more wear and tear on your rifle. 

Ultimately, choosing the right ammunition for your AR-15 will depend on your intended use and the regulations in your area.

Bayonets

Although less common than other add-ons, AR-15 bayonets still have their place and reasons for purchase. These weapons attach to the front of the rifle’s barrel, providing an option for close-quarter combat situations.

The AR-15 bayonet typically features a blade length of six to eight inches, although they can be as long as 12 inches. The blade can be either fixed or folding and can be made from a variety of materials such as stainless steel, carbon steel, or titanium. The handle is commonly made from polymer or aluminum and features different grip textures for better control and comfort.

Versatility is one of the advantages of the AR-15 bayonet. Not only can it be used for close-quarter combat, but it is also useful for cutting through foliage, prying open doors, or cutting rope or paracord.

Customizing the AR-15 bayonet is possible, with blade type being one of the most common customizations. Blades can be fixed or folding, and different materials and shapes are available. Popular shapes include tanto, clip point, and spear point. The blade material can vary from stainless steel to Damascus steel.

Another customization option is the handle. Handles can be made from various materials such as polymer, aluminum, or G10, and textures range from smooth to aggressive.

The sheath is another customization option worth considering. A quality sheath is essential for storing and transporting the bayonet safely, and materials range from leather to Kydex and nylon. MOLLE sheaths are not common, but can be found after market. 

Whether for personal collection or military use, AR-15 bayonets are a unique and functional accessory that offer versatility and customization options.

AR-15 Care & Travel Guide

Your firearm is an investment you will surely want to take good care of. Proper maintenance and care are crucial to ensuring its longevity and reliable performance. Neglecting routine cleaning and upkeep can lead to malfunctions and even permanent damage to the rifle.

In this section, we’ll discuss some of the key considerations for caring for and traveling with your AR-15.

Cleaning, Repairs, and Maintenance

When it comes to owning an AR-15, proper cleaning and maintenance is essential to ensure its longevity and reliability, which is why you should pick up a good gun cleaning kit. The frequency of cleaning your AR-15 depends on factors such as how often you use it, the type of ammunition you use, and the environment in which it’s used.

As a general rule, it’s recommended that you clean your AR-15 after every use, especially if you’re shooting corrosive ammunition or in dusty/dirty conditions.

However, if you’re not using your AR-15 frequently, cleaning it every few months should suffice. But, keep in mind that even if your rifle isn’t being used, moisture can still build up and cause corrosion. So, it’s important to keep your rifle clean and dry at all times.

Before cleaning your AR-15, make sure it’s unloaded and is safe for working on. We recommend getting a gun vise to hold the firearm in place while disassembling it. There are many cleaning kits and tools available on the market, some of which are generic and others that are caliber-specific.

While cleaning removes debris buildup, lubrication helps reduce friction and protect the moving parts of the rifle. A well-lubricated AR-15 is less likely to malfunction or jam, which is crucial during competitions or defensive scenarios. So, don’t forget to properly lubricate your rifle after cleaning it.

Regular inspections are also important to identify potential problems before they cause a malfunction. Parts such as the gas rings, extractor, and firing pin should be checked for wear and damage. If you notice any signs of wear or damage, it’s important to address them promptly to ensure the reliability of your rifle.

In conclusion, taking care of your AR-15 is similar to taking care of a car or a house. Regular cleaning, maintenance, and storage are crucial for ensuring its longevity and reliability. Develop a regular cleaning and maintenance schedule and stay vigilant for any signs of wear or damage to keep your AR-15 in top condition.

Storage and Travel Care

Firstly, before storing your AR-15 for an extended period, it’s important to clean and lubricate it to prevent rust and corrosion. This ensures that the rifle remains in good condition and functions properly when you’re ready to use it again. It’s also important to inspect your rifle periodically when it’s in storage to check for any signs of rust or damage that could lead to more serious issues later on.

When traveling with your AR-15, it’s crucial to remember that different states have different laws regarding transportation. In addition to researching the laws in your destination state, it’s important to also research any states you may pass through during your journey.

When transporting your AR-15 by air, it’s important to declare your rifle and store it in a hard case. We recommend finding a TSA compliant travel case. The case should be locked, and the ammunition should be stored separately. The weight limit for ammo is 11lbs. 

The TSA has specific guidelines regarding the transportation of firearms, and it’s crucial to check these guidelines before traveling to ensure compliance with regulations. Additionally, different airlines may have different rules regarding the transportation of firearms, so it’s important to check with the specific airline you’re traveling with to ensure compliance with their regulations.

It’s also important to remember to handle the case with care to prevent damage to the rifle or optics mounted on it. Dropping or mishandling the case can result in damage to the rifle or the optics.

Opting between a soft case or a hard case for transportation is also important. Soft cases are generally more flexible and suitable for transportation in a personal vehicle, but they offer less protection than hard cases. Hard cases are most suitable for airline travel or storing expensive rifles for maximum protection.

There are even waterproof hard cases from companies like Pelican that protect your weapon against fire and water. It’s important to choose a case that offers the appropriate level of protection for your specific needs.

Conclusion

Now that we’ve covered all the major points of the AR-15, you should have a good understanding of how this versatile firearm works, as well as the many ways you can customize and care for it. Whether you’re a seasoned shooter or a newbie to the world of firearms, the AR-15 offers endless opportunities for fun and excitement. So go ahead and build or buy your own, explore alternative calibers, and customize it to your heart’s content. Just remember to always practice safe handling and enjoy responsibly!