I would highly recommend a Geissele Reaction rod. Best AR tool I've ever bought. I've built over 100 uppers on mine. I have both the AR15 and AR10 reaction rods.
I would highly recommend a Geissele Reaction rod. Best AR tool I've ever bought. I've built over 100 uppers on mine. I have both the AR15 and AR10 reaction rods.
I own both reaction rods as well, and I wouldn't build an upper without them. It eliminates any chance of stressing the receiver and allows torque to be properly applied only to the barrel nut.