NOT KNOWN FACTS ABOUT COLT COMBAT UNIT RAIL GUN 45

Numerous rifles had been rebuilt, In particular Vietnam era rifles.  Typically the barrels were replaced.  Some samples of markings found on replacment barrels incorporate:If I'm utilizing a non-nfa course three reciever, could I set in a very "faux" sear pin on my retro Establish or would I be tempting fate?even with the AR-fifteen each of the w