TC's are the worse to own when it comes to shooting full bore projectiles. The QLA at the end of the barrels are often drilled off center and causes nothing but problems with conical bullets.
You can order a Bergara barrel for it which does great with conicals and sabots.
Blackhorn209 is the best powder out there so if you can get some, do so. I doubt it will solve your problem so i'd start looking into a new barrel IMO.
My CVA Optima @100 yards with Thor conicals. The first 3 shots and then one adjustment shot.
