Re: goin to buy a new complete upper for my AR...
Know anybody with a drill press and a welder? It's easy to do, you don't necessarily need a gunsmith to do it. There are even some writeups on it if you look around.
Basically, look closely on your current flash hider, and find the discolored spots on each side where it is pinned and welded. With a die grinder or something cut a slit down each side of the flash hider through the pin, making sure not to cut into the barrel, and then tap a chisel down into it so it splits in half off the barrel.
Then, drill a small hole in the suppressor mount behind the threading. Screw the mount on and drill through that hole into the barrel 1/8" or so, making sure not to go so deep that it penetrates into the bore. Then, cut a piece off of the back side of the drill bit that matches the depth of the hole, tap it in, and put a small tack weld over it. The small piece of drill bit goes through the flash hider and into the barrel and is welded in place, so the flash hider can't be removed without drilling out the pin. Grind the weld flush if you want, and you're done. No big deal.
