What is the difference between a 45 gap and 45 auto?

Answer 1

The .45 GAP was developed by an engineer with CCI/Speer, commissioned by Glock, to be a smaller round with the same power as a .45ACP. This was achieved essentially with powder selection. The .45 GAP has the same diameter as the .45 ACP but the case is shorter, it uses small pistol primers, and is designed for higher standard pressure to make it on par with the terminal velocity of the .45ACP round. To compensate for this increase in pressure the round has a stronger case head to prevent case head blowouts. The .45 GAP stands for "Glock Automatic Pistol" and is the first cartridge associated exclusively with Glock. The .45 GAP and the .45ACP are completely different rounds that are not interchangeable, although they perform similarly.