I've been doing this stuff with ARMALITE AR-10s and the various 15s since 1999 and never even flexed
an upper receiver or deformed/sheared an index pin.
I was warned that your rod should only be used for hand guard and FS/Brake swap outs because
of torque applied to the barrel extension's index pin. Which is exactly the opposite of what is in your
FULL DESCRIPTION of the product:
The removal and installation of barrels, flash hiders, gas blocks and hand guards is made much easier and simpler. The Reaction Rod is designed to be gripped in a bench vise so that the rod is either horizontal or vertical. The upper receiver is then slid onto the rod and the rod’s integral splines enter the barrel extension and secure the barrel extension from turning. This allows all the torque from barrel nut wrenches to go directly into the barrel extension. In contrast, receiver vise blocks transmit the turning force into the aluminum receiver, a good part of which passes through the small, easily distorted receiver index pin.
With the Geissele Reaction Rod, marring of an upper receiver’s finish by gripping and twisting inside vise blocks is eliminated and so is the need to remove sights and mounts from the receiver’s M1913 rail.
I was going to change out the DPMS LoPro with a VLTOR MUR-1A mod'd by Paladin Machine Services and the DPMS hand guard with an ARMALITE Carbine FF.
This is what I have now:
If you follow the flash glare from the gas port back to the vise, you will see that the upper receiver
decided to turn a few degrees counter-clockwise when the force vectors on the index pin told said pin to take a hike.