Started to thread an early Armalite AR10 16" SS barrel, and discovered the first inch has a false muzzle "cap"..
The first .800" of the barrel is reduced to a smooth stub about .550" diameter, and a matching stainless sleeve was slipped over this, and turned to match the barrel.
I wouldn't have ever noticed it except for the threading.
I am suspicious that one of the earlier previous owners, who is a "machinist in progress" and has all the equipment, may have attempted to thread the muzzle, botched it,
and then did this to cover it up before he sold it.
But, I don't know what the factory might have done, and am have no way of proving who might have done this, so am asking here if anyone has experience with this.
Is this something that could have been done at the factory? (can't imagine why)
Thanks