I picked up an M3 Bipod from the local surplus store cheap. Some guy getting out of the Army came by and sold all his stuff to the store. It is in a nylon sheath with 2 snaps and an alice clip on the back. It will not clip on completely and open all the way on my Bushmaster barrel although it doesn't slip and I could proboaly use it. I am assuming it is for the M-16 and is spring loaded to clip on the cut out area of the GI barrel just in front of the gas block. Is that where it is supposed to attach?

No one knows?  

They are cheap at best.  If you like it, and you think it works, go ahead and use it.  They aren't made for the M4 cutout that I've seen.

What are they issued for? I assumed the M-16 or M4 version since that is the current standard infantry weapon.  I am just curious. If I use it I may have to modify the cutouts on the bipod for a better fit to my barrel. You are right, they are sheet metal.

if you keep using that thing, you will end up asking how to remove the scratches sooner or later...

They were made for M16a1 rifles with light weight barrels.Your Bushmaster probably has a .75 barrel under the front sight base and that is why the bipod does not close completely.SJR556.

Oh well I only paid 10 bucks for it. At the least I bought myself a little piece of history. I wondered about the scratch potential.