The Mossberg 590A1 12 gauge shotgun has a bayonet lug. I was dubious at first. I own a shotgun for self defense. I’m not taking it to war. I indulge in the occasional zombie massacre fantasy, but not seriously enough to seek out a bayonet. So when the Mossberg came in with a bayonet lug, I didn’t think I would ever find a practical use for it.
After all, a bayonet would block a forend light, something I consider very useful on a self defense shotgun. Still the 590A1 has a bayonet lug, so I had to put a bayonet on it. You know, just because.
The Ontario Knife Company sent an OKC3S for me to put through the paces. And as ideal at the bayonet is for an M4, it didn’t fit on the Mossberg. After some phone calls, and some talks with a technician or two, Mossberg sent their preferred bayonet, which is also an Ontario Knife Company bayonet: the M9.
The M9 is the current bayonet being issued to infantry troops. The blade is suitably thick, close to 1/4 inch. The whole bayonet is just over 12 inches, and seven inches of that is blade. The blade is a black oxide coated stainless steel. The handle is nylon, and so dense that it almost feels metallic. The scabbard is amazing, and equipped with a screw driver and a wire cutter.
If you aren’t being issued one, you can expect to pay somewhere right around $100 for an M9. But it’s worth it. The knife is useful as a cutting tool, and capable of handling abuse.
The Marines are now using the OKC3S. The OKC3S is similar, but the differences are significant. Instead of the stainless steel of the M9, the OKC3S has a carbon steel blade. The handle is a bit more ergonomic, which is an acknowledgement that you will want to hold it in your hand, too. The scabbard is more MOLLE friendly, and the blade slides into and, more importantly, out of it with next to no noise.
The OKC3S feels more like an honest fighting knife. It is just slightly larger than the M9, with an inch more blade, but it feels a bit bigger than that. And the price is a bit higher. Recent sale prices dropped below $100, but that’s rare.
Why put a Bayonet on a Shotgun?
I still think this is an interesting question. I can see one really obvious use, and that’s the same reason why anyone would put a bayonet on an M4, or any military rifle.
There is another compelling use, and one I had missed. Some hog hunters use big rifles equipped with night vision scopes that cost more than my car. Others get a bit closer to the action, and use shotguns. The bayonet makes a really effective pig-sticker, and could be a good last result if you run a shotgun dry.
The Bayonets on the Mossberg 590A1
The Mossberg 590A1 would be a great pig gun for close range hunts. And the M9 is Mossberg’s recommended bayonet. I figured that out only after the OKC3S didn’t fit. The handle of the M9 comes in 1/4 inch shorter than the handle of the OKC3S. And that makes a huge difference on the magazine tube cap, where a bayonet hilt connects to a shotgun.
Why the discrepancy? I’m not sure. No one that I talked to at either Mossberg, or Ontario Knife Company had heard of this issue, exactly. And there isn’t much that can be done to the bayonet. If you really want to use a OKC3S on a 590A1, you will need to extend the length of the magazine tube cap.
I found a simple fix. A 1-inch lock-washer, modified just a little bit, will fit behind the cap, and make up the difference. The OKC3S then fits snug on the cap, and snaps onto the rear lug, no problem.
I’m simply offering this as a proof of concept. I’m not suggesting that anyone else attempt this fix at home; far from it. The cap holds on the magazine tube, which has to be in place to keep the barrel in place. The consequences for screwing it up could get really ugly.
Clearly this isn’t for everyone. But a bayonet has its uses. And the Mossberg 590A1 is designed just for such uses.
And the bayonet doesn’t have to block a light. I replaced the forend with a Talon from ATI, and attached a SureFire Scout Light on the Talon’s angled forend. Now if I can only find a pig or two that might be willing to let me test the whole package.