First off, I want to apologize ahead of time if I’m doing any of this wrong.
Ok, I am trying to put together a precision rifle from my AR pistol lower. I’ve decided to put a 6.5 Grendel complete upper on it with a FAB Defense RAP stock. I chose a 20 inch heavy stainless barrel, rifle length gas system and has the .750 gas block. My question is where to start with the buffer tube, spring and buffer?