T/C thumbhole laminate stocks are pretty notorious for sloppy fit. The action moves around every shot. This will be evident with a wide pattern (bedding will fix this). If the barrel has large and small sections in it, it will show up as an up and down string due to varying pressures. If it's just rough a lilltle polishing with a MILD abarsive and steel wool saturated with oil should help. Try some different sabots for fit. If it is a fifty, maybe all you need is a .452 bullet. Had combinations of these problems with 2 different X-7's. And yes, T/C will try to fix it for you. Talk to someone in the custom shop, not the receptionist. Oh, and quit using the bore butter. My old Black Diamond would drive tacks after 20 or so shots to burn out the bore butter each time!