Originally Posted by
556Cliff
The "new" Reaction Rod is known as the Super Reaction Rod and it has two brass wedges that fit through the ejection port that stop the upper from being able to rotate against the index pin. The brass wedges also preload the barrel extension lugs against the lugs of the Reaction Rod in the direction of torque you choose (loosening or tightening).
The brass wedges make it an absolute bitch to install a barrel with the torque three times to 30 foot pounds barrel installation method as found in the tech manuals, because before you change the direction of torque you have to readjust the brass wedges every time you do so.
As for lubing the threads AeroShell 33MS meets the spec, you put it on the threads of the upper receiver, on the threads of the barrel nut and the outside surface (side facing the FSB) of the barrel extension. Iraqgunz uses loctite C5-A but that contains graphite and is considered a no-go by most guys on the forums, I used to use Brownells Barrel Assembly Paste which contains 65% moly but this was discontinued, now I use T S Moly TS-70 moly paste which contains 70% moly.