if the barrel came from a class 3 that saw a lot of use the barrel might be worn out. a decent smith that is familiar with ar15 can tell you. but its something that has to be hands on.
"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