I'm building an A1 clone. I got a USGI Colt barrel for free luckily, but I feel kinda bad cutting the GI FSB to neuter the lug. There's a chance I'll be moving to PA in the nearish future, so I'm considering buying a used A1 USGI FSB and keeping it on hand for if I move. Can a competent Smith mate a used FSB with a used barrel?

1. There's no guarantee that the holes on a used FSB will line up correctly with those on the current barrel.

2. Keep in mind if the barrel is threaded, you're going to have to get the muzzle device pinned. That would require that you destroy that muzzle device in the future in order to swap out the FSB again.

3. If the barrel is not threaded, you can swap the original FSB for a gas block with a built in front sight.

Adco can do it, but it's kind of expensive, and I'll echo what Nikos said above.

 

Why don't you just grind the ears off the bayonet lug so that a bayonet cannot be attached?

What are the chances of you using a bayonet on your rifle anyway???