My rear ring of the gas cylinder is tight to the barrel at the 9:00 to 6:00 postion as viewed from the muzzle. I'd like to open it up so it doesn't touch. How tricky is this? Also, the cylinder is a bit loose in the splines........should I try to peen them? I get consistent flyers, a nice group of 3 or 4 then a very wild flyer several inches from the group. Barrel seems OK and TE is a 2.