Thats whats so puzzleing to me about muzzleloaders. Bore sizes seem to be all over the place. Especially on the CVA and traditions. Thats the main reason I have stuck with the knights, they seem to be decently consistent. But still find variations on pushing down sabots from my gun to others. I think that will explain why I see some getting great groups and very consistent velocities out of the power belts and other say they get 250fps variations.