In the process of switching some parts around, I noticed that my barrel nut was loose on my RRA 9mm upper. So I tightened it down with a barrel wrench which is one of those USGI issue wrenches that is rectangular. One of the 3 prongs on the wrench for the barrel nut is broken and when I tightened as far as it could go and  reinstall the handguards and I could not get them to line up with the front sight. But if I leave it (barrel nut) too loose the handguards line up but I can move them around. Any help would be appreciated, and yes I know I need a new wrench.