I’m having issues with my Glock 17 with a KKM barrel and SJC comp. At 15 yards I would often get the first round 6 to 8 inches below the “group” if you want to call it that. The Group would be large, 4+inches, and inconsistent in on where it hit, changing from one range session to the other. As a last resort I pulled the comp off and the gun shoots nice tight groups. The comp was not touching the slide, I made sure of that.
Any ideas?