The AR-10: The Innovative Force Behind the AR-15

History of the AR-10

The AR-10 – originally called the ArmaLite AR-10 – was designed in Hollywood, California by engineer Eugene Stoner and was overseen by small arms inventor Jim Sullivan for the U.S. Army’s 1956 rifle trials in order to find a suitable replacement to the M1 Garand for infantry use. The AR-10 lost the competition to Springfield Armory’s M-14, both chambered in the 7.62x51mm. ArmaLite’s submission, the AR-10, had entered the competition late. Unfortunately, the AR-10’s untested aluminum composite barrel — a requested feature by Sullivan, though Stoner protested — proved to be its undoing; the rifle’s barrel exploded during a 7,500-round torture test which caused military officials to rule against adopting the AR-10 for any future campaigns. In the end, military officials greenlit the M-14 for mass production. 

While it was selected for deployment by the United States Army, the M-14 rifle fared little better than the AR-10 in terms of battle-readiness and overall utility, as it came to have several design flaws which caused it to underperform – or seize outright – on the frontlines of battle. The M-14 began being phased out of American military engagements shortly after its arrival in Vietnam which pressed U.S. gun manufacturers to design and build its replacement. 

Shortly after the trials in 1957, and with no burgeoning interest from stateside military markets, Armalite looked to international markets to secure a small arms contract which they eventually found in Artillerie-Inrichtingen (A.I.), a state-funded Dutch armament company of the time. A.I. engineers found a number of manufacturer defects in the demonstrator versions of the AR-10 rifles that they received from Armalite. In their effort to recalibrate the seemingly faulty design of the Hollywood-made trial versions of the AR-10, A.I. worked alongside Armalite to rebuild the AR-10 rifle from the ground floor so that widespread production could commence.

Once production was underway, the newly renovated A.I. model of the AR-10 not only sold well and saw combat in neighboring countries like Guatemala and Cuba, but the rifle also took part in several overseas military campaigns in Portugal, Italy, Burma (now Myanmar), and Sudan.

During that same year, ArmaLite entered another U.S. Army design competition for a new, accurate, infantry rifle chambered in .22 caliber. Eugene Stoner, Jim Sullivan, and the ArmaLite team pulled from the AR-10 platform to design the AR-15 chambered in .223 Remington/5.56mm. The AR-15 won the U.S. Army’s tests and the full-auto M-16 was born. ArmaLite tried to sell the AR-10 and AR-15 simultaneously, but as the AR-15 gained significant interest, the AR-10 received no orders from either foreign or domestic military markets. 

Despite the success the AR-10 saw in military engagements in several countries as the fifties were drawing to a close, Armalite pulled Artillerie-Inrichtingen’s license to produce the rifle. Armalite’s decisive action to cancel its contract with A.I. was taken due to the limited number of AR-10 rifles in circulation and an increasing delay in both production and exportation of the weapon because of a looming weapons embargo which began to take shape in the Netherlands at that time. 

Colt Firearms purchased the rights and designs of the AR-10 and AR-15 in 1959. ArmaLite was facing financial difficulties and limited firearm production knowledge, leading to the sale to Colt, a much more established firearm manufacturer.

In the early 90s, Stoner joined Knight’s Armament Company where he continued his AR-10 design work and joined it with the direct gas system of the AR-15. The end result was the SR-25 in 7.62mm NATO (adding together the call sign numbers of the AR-10 and AR-15) which improved the AR-10 design with M-16A2 advancements and parts commonality.

In 1995, the then defunct ArmaLite brand was purchased and re-opened for business. The AR-10B was introduced which is based on Colt’s AR-15A2 and is chambered for both 7.62mm and .308 caliber cartridges.

ArmaLite is still producing the AR-10 today and a complete selection is available through local dealers.

AR-10 Design

The AR-10 is designed to be a lightweight, low-recoil, gas-operated, and magazine-fed rifle where the bolt carrier acts as a movable cylinder and the bolt as a stationary piston. This design allows the removal of the conventional gas cylinder, piston, and actuating rod assembly, saving both space and overall heft. One of the main benefits of the AR-10 is that it’s easily customizable and can be built in a number of different ways depending on shooter preferences.

AR-10 Pros

The AR-10 is a great rifle for long-range shooting and hunting. The 7.62mm cartridge provides more power and better penetration than the 5.56mm which make it a great choice for shooting at longer distances. Furthermore, a scoped AR-10’s effective distance is 200 yards more accurate than that of the AR-15 at the same distance.

When hunting large game like deer, black bears, or boars, the larger bullet of the AR-10’s 7.62MM cartridge will add more stopping power than the AR-15’s 5.56mm ammo.

The AR-10 is more accurate than the AR-15. The heavier bullet of the 7.62x51mm cartridge means less muzzle rise and recoil which make it easier to stay on target for follow-up shots.

Cons

One of the main setbacks of the AR-10 platform is the fact that it’s more expensive than the AR-15. What’s more, the 7.62x51mm cartridge is also less commonly available than the 5.56x45mm in the United States which makes that caliber of ammunition harder to come by. That said, 7.62x51mm ammo is more widely available for purchase via online sellers and storefronts. 

The AR-10 is a bit heavier and bulkier than the AR-15, especially with the heavier 7.62mm/.308 cartridges, so it may not be ideal for carrying long distances or in tight spaces.

AR-10 Calibers

The AR-10 platform is also available in a number of different calibers:

• 7.62x51mm NATO
• .308 Winchester
• 6.5 Creedmoor
• 7mm-08 Remington
• .260 Remington
• .243 Winchester

AR-10 Specs

• The AR-10 is a gas-operated, rotary bolt action rifle that uses direct impingement.
• The rifle has a detachable box magazine with a capacity of 10, 20, or 30 rounds.
• The AR-10 has a 16” barrel (though some models with 18” barrels are available for civilian purchase).
• Overall length of 36.5”-39”.
• It weighs in at 7.8-9.5 pounds, depending on the model.
• The AR-10 has a muzzle velocity of 2,700 feet-per-second and an effective range of 600 yards.

AR-10 vs AR-15

Caliber

The AR-10 uses the larger and more powerful 7.62x51mm NATO/.308 Winchester cartridge. The AR-15, on the other hand, fires a smaller 5.56x45mm NATO/.223 Remington cartridge.

Power & Penetration

The AR-10’s 7.62x51mm round has more power and better penetration than the 5.56x45mm of the AR-15 which makes it a better choice for long-range shooting and hunting. This considerable increase in power is due to more gun powder in the cartridge and the larger size of the bullet overall.

Accuracy

The heavier bullet of the 7.62x51mm cartridge means that there is less muzzle rise and felt recoil by the shooter which makes it easier to stay on target for follow-up shots.

Weight

The AR-10 is a bit heavier and bulkier than the AR-15, especially with the heavier 7.62mm/.308 cartridges, so it may not be ideal for carrying long distances or brandishing it in tight spaces.

Ammunition Availability

In the United States, the AR-15’s 5.56mm is easier to find than AR-10’s 7.62mm. While in other countries – especially in Africa, Asia, or Europe – the opposite holds true, as the AR-10’s 7.62mm NATO cartridges being the gold standard where ammo is concerned.

Which rifle is better? It honestly depends on the situation. For long-range shooting or hunting, the AR-10 is a great choice. For a lighter, more compact rifle for personal defense or close-quarters engagement, the AR-15 would be a better option. But at the end of the day, the AR-10 and AR-15 are both known for being dependable rifles.

7.62mm NATO or .308 Winchester: What’s the Difference?

The 7.62mm NATO and the .308 Winchester use the same size bullet and are related. But the .308 Winchester was the “parent” casing for the 7.62mm NATO round because NATO needed a cartridge that would allow for different chamber sizes while withstanding the wear and tear of automatic fire.

The biggest difference between the 7.62mm NATO & .308 Winchester comes down to two things: internal dimensions – brass thickness and barrel chamber length for the different cartridges. In short, the 7.62mm NATO and the .308 Winchester cartridge casings come down to the chambers they are designed for. Manufactured .308 Winchester and 7.62mm NATO rounds can safely and effectively be fired in rifles designed for .308 calibers. However, manufactured 7.62mm rounds should only be shot within rifles designed specifically for 7.62mm calibers.

Utility of the AR-10

The AR-10 is popular among competitive shooters and hunters. Many competitive shooters use the AR-10 in .308 Winchester or 6.5 Creedmoor for long-range shooting matches. The 6.5 Creedmoor has become increasingly popular in recent years due to its excellent accuracy and moderate recoil.

Hunters also commonly use the AR-10 in .308 Winchester or 7mm-08 Remington for hunting deer, elk, and moose. The AR-10 is a great choice for hunters who want the power of a larger caliber weapon, but don’t want the weight and bulk of a traditional bolt-action rifle.

The AR-10 is also a popular choice for home defense. The .308 Winchester/.30-06 Springfield cartridges are great for long-range shots and the 7.62x51mm NATO cartridge can penetrate both walls and reinforced barriers. The AR-10 is also more rugged and durable than the AR-15 which makes it a viable rifle to use from a defensive position.

Countries that employ the AR-10

The AR-10 is currently an active service weapon by militaries and law enforcement agencies in the United States, Canada, France, Spain, Italy, Portugal, and Brazil, all of which use variants of the AR-10 in their respective armed forces.

SR-25

The SR-25 is loosely based on the AR-10 because up to 60% of the SR-25’s parts are interchangeable with the AR-15 and the M-16 which means that militaries need to carry fewer specialty gun parts into battle.This build-type afforded the SR-25 an innate flexibility to its overall accuracy which proved useful for sharpshooters in the following countries:

•  Australia: Australian Army, Royal Australian Air Force Airfield Defense  

           Guards, and Police Tactical Groups.

•  Israel: IDF Special Forces
•  Philippines: National Police Special Action Force and the Army Light   

           Reaction Regiment

•  Poland: GROM
•  South Korea: Republic of Korea Navy Special Warfare Flotilla
•  Thailand: Royal Thai Army
•  Turkey: Gendarmerie General Command
•  United States: Special Operations Command, Marines

Other AR-10 Style Rifles

ArmaLite still owns the rights to the “AR-10” name; however, other manufacturers have produced other rifles that are similar in design and function. These models are all 7.62x51mm NATO auto-loading rifles based on the AR-10 design, but they have minor adjustments that make them more modular than the AR-10B or the original AR-10 itself.

AR-10 Style Rifle Manufacturers

• Adams Arms PD1
• DPMS LR-308
• Knights Armament Corporation SR-25
• Knights Armament Corporation M110 Semi-Automatic Sniper System
• Rock River Arms LAR-8
• JP Enterprises LRP-07
• American Spirit Arms ASA .308
• Fulton Armory Titan
• LWRC’s R.E.P.R
• CMMG’s MK3
• LaRue Tactical’s OBR
• RND Manufacturing’s “The Edge”
• Oberland Arms OA-10
• Lewis Machine and Tool LM308MWS
• Bushmaster MOE 16 .308
• Daniel Defense DD5
• Palmetto State Armory PA-10
• Seekins SP-10
• Brownells BRN-10
• SIG Sauer 716i
• Smith & Wesson M&P10
• Windham Weaponry SRC-308
• Colt Canada C20 DMR

Conclusion

Decades later, The AR-10 has maintained a proven track record with militaries and law enforcement agencies around the world as a viable service weapon. The AR-10 has also become a favorite among competitive shooters and hunters, as well as a popular choice for both personal and home defense which is why AR-10-style rifles are still being produced by several different manufacturers today for their rugged craftsmanship, utility, and dependability. If nothing else, we must pay homage to Eugene Stoner and ArmaLite for creating the AR-10 because it single-handedly paved the way for what was to become the most sought after rifle by U.S. military and law enforcement today – America’s Rifle – the AR-15.

Justin Trump

Justin Trump is the managing editor and owner of CAT Outdoors. The son of a Vietnam veteran, he’s an avid gun enthusiast and 2A advocate. He holds two firearm patents for the CAT M4 and Talon tools. When not managing CAT Outdoors, he enjoys spending time with his family and friends, rooting for Michigan sports teams, and serving his church.