Quote Originally Posted by Bruce Canfield View Post
Be very careful and remember that a Model 870 fitted with a bayonet adapter is not a Mark I. The Mark I guns were made by Remington under a 1969 USMC contract and there several features specific to the guns. Genuine Mark I shotguns are extremely rare "on the loose" but Model 870 shotguns fitted with bayonet adapters are fairly common. Some were fitted with the adapters under government auspieces. Most weren't.
I used them on active duty. Have never seen the real deal outside a USMC Armory. I do have a USMC adapter, barrel and extension tube mounted on a 870 Express. I was a Combat Shotgun Instructor for the USMC Security Force Bn Pac. I found the adapter, barrel, and extension at a LA gunshow at the Fairgrounds there. The seller was a retired USMC Armorer, where he got it I have no idea. I was teaching at NS Long Beach and the Navy was using Mossberg 500's. I had my Express set up like a MK I. I used it to teach the Combat Shotgun Course. Still have it and will keep it, not many folks can say that they have a gun they used on active duty.