I feel your pain. My friend loaned me his .45 XR to tweak the scope. I was with him last year when he attempted to sight it in, with thesame jumping patterns. He was unable to load anyT/C sabots into the barrel. He switched to Powerbelts and would keep themscattered on target. I was shooting 150pellets and 195 power belts. Wow what a kick! First four shots were left and right. Swabbed the barrel, dropped down to 100 grains.Went to1600, then to a perfect 1800 shot, next was a perfect bullseye. Next four were scattered of the target and one 3 inches off. Scope was not the problem. I suspected it may be one of the older 1/20 twists. I'll try a 295 grain next due to tight twist. PS what a pain in the a$$ design to remove the breech plug and striker. My very old LK-93,gave a 1 inch, four shot cluster using 90 RS and a 300 .45 XTP..