Want to share my ammo test results. Shooting a PBBA 457 Carbine. Great accuracy from High Arc Hunter bullets. Shot sizes from 240 gr to 475 gr good groups from all. But really good from heavier bullets including the 475 gr monster, which shot three shots touching..sorry didn't get pic of 475.
Barrel length is only 20". I get two full power shots. Third shot usually bout an inch low. Haven't shot 100 yards yet. Will stretch it out there soon.