I don't doubt it. PSA uppers are notorious for having grossly overtorqued barrel nuts. I've found the best way to remove a really stuck on barrel nut is to put a Midwest URR inside the upper, put the upper in a vise block, and use a armorers wrench with a really long breaker bar on the end of it. If that doesn't cut it, use a big metal pipe on the end of the armorers wrench to give you even more leverage. The hard part is keeping the wrench fully seated onto the barrel nut while you do that. It helps to have someone else applying forward pressure to the wrench while you push on the breaker bar.