Buffalo Bore Ammunition 7C/20: The 454 Casull is one cartridge that Buffalo Bore Ammunition does not load to its full pressure limit. When loaded to its full pressure potential, the 454 Casull can become unreliable and unpleasant to shoot, and at upper pressure levels, heavy bullets tend to jump crimp, tying up the cylinder. The 360-grain bullet at 1425 fps is very powerful, comfortable to shoot, and totally reliable. At this level, these bullets give up nothing in killing performance.