| Basically they were a stainless steel collar that was bolted into place in the lower tube by your beaver-tail screw. Inside was an IVG that had two notches in it as well as the original hex-key hole for the cocking rod to run through. Those two slots correspond to a metal "key" that has a slot cut in it that allows you to place it around the cocking rod and use the two tabs on the bottom of the "key" to move the IVG in or out to fine tune your velocity. They worked well, but can be a pain to keep in place while you're trying to screw/bolt everything together. |