I have a Mossberg 500 with the bayo lug and heat shield. I don't know much about the gun as I bought it used. On a whim I bought an M16 bayonet for it, after all it had the lug for it. The problem is that the bayonet doesn't fit properly. It won't lock in place. I can see what the problem is. The bayonet bottoms out on the lug before it goes in far enough to lock. A simple fix would be to file or grind the lug so that the bayo. would go in far enough to lock. Or I could Dremil on the bayonet. I have the shotgun for home defense and coyotes. Is a bayonet a good choice for a home defense shotty? Should I modify the gun, or the bayonet? I might add that the bayonet fits real well on my RIA AR 15. Your input is appreciated.