Typically not welded.
Just need a wrench a vice and some wooden blocks with slight groove to clamp the barrel.
Having a buddy hold the gun and twist can do serious damage to the upper receiver and torque the help out of the gas system leading to all sort of fun hard to resolve issues.
Also an upper receiver block or receiver vice is not for attaching or removing muzzle devices as it can cause the same issues as bubbaing it off with a buddy
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent
Last edited by JonM; 01-23-2014 at 08:50 PM.