I removed a known good barrel and installed it into a new build, the new upper is a Spikes Tactical in FDE cerokote. Having done this dozens of times, it was business as usual. I used a vise, Geissele Reaction rod, and a torque wrench… fully assembled, I went to the range.. I installed the same Bolt carrier group as well. Groups were abysmal! 8”-10” at 100 yards and all over the place, recoil was stiff, bolt swipe was deep, and had 1 blown primer.. tried 2 Hornady factory loads and American Eagle. (Just a couple of each) even wolf steel case was showing high pressure. What caused this? My only thought is the barrel extension twisted. Upon case inspection, it seemed like the Hornady brass case mouths were contacting the lands possible.. ding marks.
