The .45 GAP has the same diameter as the
.45 ACP pistol cartridge but is slightly shorter, and uses a small-pistol primer instead of the large-pistol primer most commonly used in .45 ACP ammunition. Originally, the maximum bullet weight of the .45 GAP was . In order to provide terminal ballistics that matched the standard .45 ACP loads, the .45 GAP was designed to operate at a higher standard pressure—roughly equivalent to the higher pressures found in .45 ACP
"+P" rounds. Since the .45 GAP has a much smaller cartridge volume than the .45 ACP, the desired pressure and resulting velocity needed to be achieved through powder selection alone. Later development concluded that the .45 GAP can also fire projectiles, as does the .45 ACP; though this pushes the .45 GAP cartridge to its limits.
Glock .45 GAP pistols The full-size
Glock 37 pistol was introduced by Glock to use the .45 GAP cartridge and was followed by the compact Glock 38 and the subcompact Glock 39. Glock's .45 GAP–sized pistols use the same frame as their 9×19mm/.40 S&W/.357 SIG line of pistols. The slide is slightly wider to accommodate the larger diameter .45 round and is flush with the frame. Magazines for the .45 GAP are of the same dimensions as those of the 9×19mm/.40 S&W/.357 SIG line of pistols.
Other .45 GAP firearms Initially, due to its acceptance by law enforcement and the popularity of subcompact handguns for
concealed carry, a small number of manufacturers decided to produce pistols that were chambered in .45 GAP, but they no longer produce any pistols in that caliber. Only Glock continues to manufacture pistols in the .45 GAP cartridge.
Springfield Armory, Inc. did make the
XD series in .45 GAP, and indeed it was the first commercially available pistol for it, but discontinued that chambering soon thereafter. ==Law enforcement applications==