I have a Colt M4 Match Target 6400c. My question is what would be the cheaper way to go: buy New
barrel (with threads ), Buy new complete Upper,or take it to a gunsmith to have the barrel cut down and threaded. as you can tell I'd like to get rid of the muzzle brake and put on a flash hider. Installing a new barrel does not look too hard...anything to look for when removing old barrel and installing new one? has anybody done this already ? If I bought a complete Colt upper do they just drop in and go ?