OKC 498 Marine Combat Knife Review: Not a Bayonet, Still Worth Your Money

Half the internet calls the OKC 498 a Marine bayonet. It won’t mount to your rifle, and no adapter on the market changes that.

What it’ll do is put the Marine Corps fighting knife on your belt for about fifty bucks less than the famous version of the same blade. Here’s what the 498 actually is, why the bayonet label keeps sticking to it, and who should buy one.

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OKC 498 Marine Combat Knife

The Marine Corps fighting knife, built by the company that has held the contract for decades, at $48 less than the Ka-Bar-stamped version of the same pattern. Sharpen it, oil it, carry it.

Where to Buy

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Can You Mount It to a Rifle?

No, and the reason is mechanical rather than legal. A bayonet needs two pieces of hardware, and both are machined into the knife at the factory:

• A muzzle ring in the crossguard that slips over the flash hider and carries the weight.
• A T-slot in the pommel, with a spring catch, that drops onto the rifle’s bayonet lug and locks.

The 498 has a straight steel crossguard with no ring in it and a solid steel butt cap with no slot. There’s nothing to slide over the barrel and nothing to latch onto the lug.

Search “bayonet lug adapter” and you’ll find a shelf full of hardware, but all of it runs the other direction. CAA, ProMag, and KZ sell adapters that clamp onto a bayonet lug you already have and give you a Picatinny rail for a light or a laser. APG Defense sells a lug extender that does the same job further out. Those parts add a rail to your rifle. None of them add a ring and a locking slot to a knife, because that’s a machining operation, not a bolt-on.

Clamp-on rifle knives do exist. Firefield sells one around $30 with a barrel mount in the box, and the reviews on it read more like a visual deterrent than a knife. Those are complete systems: the mount is designed around that one blade. You can’t feed a 498 into one.

The 498 rides on your belt. That’s the whole story.

If you want a Marine blade that genuinely locks onto a rifle, buy the OKC-3S. Eight-inch blade, the bayonet the Corps adopted in 2003, and it runs $125 to $155 depending on the day. It’s the Best Fighting Bayonet pick in our AR-15 bayonet guide.

Why Everybody Calls It a Bayonet

The confusion is earned, because the Corps carried both and the names ran together. The 498 descends from the 1219C2, the fighting-utility knife the military adopted in November 1942 after the Mark 1 kept snapping blades. Marines called it the “Ka-Bar” after the tang stamp on Union Cutlery examples, and the nickname attached to the pattern instead of the maker. It was never a bayonet. Marines carried it next to whatever bayonet their rifle happened to take.

The actual Marine bayonet went a different path: the M7 through Vietnam, then the OKC-3S in 2003. The OKC-3S looks like a Ka-Bar that spent a winter in the weight room, same silhouette but bigger, with a muzzle ring and a latch. Ontario builds both knives. Both get called “the Marine knife” at gun shows. That’s how a fighting knife ended up with a bayonet listing.

The Spec Sheet, Decoded

Seven inches of 1095 carbon steel, clip point, fuller down the flat, zinc phosphate finish. Stock thickness is 0.165 inches, hardness runs 55-58 HRC, overall length is 12 inches, and the handle is stacked leather washers between a steel guard and a steel butt cap.

Here’s what those numbers do in your hand. 1095 is plain high-carbon steel: it takes a scary edge on cheap stones, holds a working edge through real use, and starts rusting the minute you forget about it. That 55-58 hardness sits soft by 2026 super-steel standards, and it’s deliberate. Soft enough to bring back on whatever stone is in the drawer, tough enough that the edge rolls instead of chipping when you hit something you should not have. If you want the longer version of that trade-off, we broke it down in carbon steel vs. stainless for tactical knives.

One myth while we’re in the specs. Dealers list this knife with “blood grooves” right in the product title. That channel is a fuller, and it’s there to cut weight and stiffen the blade, the same reason an I-beam isn’t a solid bar of steel. Blood has nothing to do with it.

The zinc phosphate coat kills glare and slows corrosion on the flats, but the edge itself is bare steel. Wipe it down. That’s the whole contract with carbon steel.

Ontario vs. Ka-Bar: Same Pattern, $48 Apart

Both companies build this knife to the same government drawings, so the 498 isn’t a clone of the famous one. It’s a second source for it. At KnifeCenter in early July 2026, the Ontario 498 runs $66.58 and the Ka-Bar 1217 runs $114.95. Same 7-inch 1095 blade, same 12-inch overall, same stacked leather, same leather sheath.

Four differences actually matter:

• Ontario coats the leather. Owners on BladeForums point to the black weatherproofing on Ontario’s washer stack as the reason it shrugs off dry rot in wet climates. Ka-Bar polishes theirs bare.
• Ka-Bar ships sharp. Ontario often doesn’t. Owner reports on the 498 run to “dull as hell from the factory.” Budget twenty minutes on a stone before you carry it.
• Different coatings on the furniture. Ka-Bar powder-coats the guard and butt cap; Ontario runs the same zinc phosphate as the blade.
• The tang stamp. U.S. ONTARIO instead of KA-BAR USMC. That matters at a collector table and nowhere else.

Buy the Ontario. Put the $48 you saved into a stone and a bottle of oil, and you still come out ahead.

What to Know Before You Buy

This is a 1942 design doing 1942 things, and it asks for a little discipline in return:

• Plan on sharpening it first. See above. The steel takes an edge fast, so it’s one evening, not a project.
• Never store it in the sheath. Leather holds moisture against 1095 like a sponge taped to a battery terminal. Hang the knife and the sheath separately, both dry.
• The guard can loosen over years. Stacked leather shrinks as it dries out. That’s a trait of every washer-handle knife on earth, Ka-Bar included, and a soak of leather conditioner heads it off.
• It’s not a pry bar. The thin clip point is a slicer. Batoning firewood with it is how you learn about the 1219C2’s tang.
• The sheath is friction retention and nothing else. It hangs off a belt fine. A nylon sheath with a pocket for a stone is a cheap upgrade we would actually make.

Plain edge, no serrations, not stainless, and no do-everything survival tool. If that’s the job you’re hiring for, our SHTF gear guide points at better options. The 498 is a fighting knife that moonlights as a camp knife, and it’s very good at exactly that.

The Franklinville Wrinkle

Ontario Knife Company as you knew it ended in 2023. The Franklinville, New York factory closed on July 27, 2023, and 56 workers went home. Five days later, Blue Ridge Knives bought the OKC name, designs, and inventory from Servotronics for about $2.1 million, and production has since been moved and contracted out.

Dealer shelves now hold a mix of old-factory and newer stock, which is exactly why one listing says $67 and another says $129 for the same SKU. Ask the dealer what they’re shipping before you pony up the dough, and don’t pay a $60 premium for a knife somebody is calling collectible because of a tang stamp.

The Verdict

At $67, the 498 is the cheapest honest way into the real issued pattern: no collector premium, no marketing story, an actual government paper trail behind it. Ontario has been building this knife on contract for decades, and 1095 at this hardness will outlive you if you keep it oiled.

So here’s the play. If you came for something that clamps onto a rail, start with our AR-15 bayonet guide and look at the OKC-3S or the M9. If you want one honest 7-inch fixed blade on your belt, buy the 498 at the $67 price, sharpen it the night it lands, keep it out of its sheath, and put it to work.

Ready for more? Check out our Best AR-15 Bayonets guide, the OKC 494 M7 bayonet review, and our Best AR-15s list.

Justin Trump

Justin Trump is the managing editor and owner of CAT Outdoors. The son of a Vietnam veteran, he’s a Certified Glock Armorer, 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.