Reaction Rod:
This thing is AWESOME! It will secure a Barreled Upper receiver solidly in the vice. It inserts into the chamber lugs and that is what makes it awesome. Your UPPER can be rotated like 10-15 degrees at a time, dependent on what you are working on. For example, if installing a quad rail, and the mounting screws/bolts are on the back side of the rifle as orientated in a standard clamshell type upper receiver block, you only have 2 options, reverse the mounting block. This requires loosening of the vice jaws as well. Not with the reaction rod.....no need to loosen vice at all. PULL upper out an inch or so, and rotate it until you have the most ergonomic orientation for your task. Another benefit is when torquing a barrel nut. There is little to no stress applied to the upper receiver at all. All of the stress is taken by the chamber lugs. So, reduced fear of torquing/stressing your upper.
Only CON I have come up with is:
YOU must have the ROD secured solidly in the vice. My competition HBAR barrel and quad rail with weights makes the upper receiver significantly heavier (by like 7-10 pounds)......when I went to remove a barrel nut the rod came loose a little and canted itself in the vice. My vices teeth/jaws are not the best, so.....I had to really TIGHTEN it on there. Caution because nothing worse than installing a new barrel and the crown or the optic gets damaged if it slips out.
SO..., that is my review. There are YOUtube Vids on it, here is one:
https://www.youtube.com/watch?v=fFMoxC5T5GY
Link to Geissele:
https://geissele.com/tools/reaction-rod.html
And a few pics of me using it:
I highly recommend this as a standard tool to any DIY Armorers kit.
R/
Chris