I've been looking at two different types, one that holds the upper receiver itself, and the other has lugs that interface the bolt lugs of the barrel and relieve the stress placed on the receiver by holding the barrel lugs themselves. Can the barrel lugs withstand the torque (up to 80lbs I think?) of installing a barrel? I'd rather risk the ruin/bend/break/crush/destroy an $80 upper than a $350 barrel, but if the barrel lugs are designed to withstand the force I can see where this is potentially the best route. I know the US Military method involves gripping the barrel itself in a vice, but I really don't want to mar the finish of the rifle barrel either. Opinions?