Have a CVA Apex and Accura V2 in 50 cal. Both shoot Barnes 250gr TEZ in a Harvester sabot very well with 110gr BH209.

First shot flyer is very frustrating. Our two TC's seem to be the worst with that. The CVA's, my Knight Elite, and custom Remington muzzleloaders don't have first shot flyers.

I remove the oil in the barrels with an alcohol patch followed by a dry patch then pop 3 primers to foul the bore.