The .45 GAP cartridge (.45 Glock Automatic Pistol) is an Austrian .45 caliber cartridge developed by GLOCK for the GLOCK pistol. It was developed in order to try to fit a .45 caliber cartridge in a compact 9mm/.40 caliber GLOCK frame. In other words, it was designed to be equivalent to the .45 ACP but to hold more rounds.

It appears to be a short and fat version of a .45 ACP, but operates closer to a .357 SIG, designed to operate at higher pressures with more power. It's also more modernized and updated, correcting design flaws of the .45 ACP.


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 200 grains (13 g). In order to provide terminal ballistics that matched the standard 230-grain (15 g) .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 could also fire 230-grain (15 g) ammunition as does the .45 ACP.

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. The manufacturer lists the width of all three pistols as 1.18" wide, compared with 1.27" for the .45 ACP Glock 21 and Glock 30, indicating that Glock could shorten the grip width and front to back grip size. Glock's .45 GAP sized pistols use the same frame as their 9mm/.40cal/.357SIG line of pistols. The slide is slightly wider to accommodate the larger diameter .45 cal round and is flush with the frame. Magazines for the .45 GAP are of the same dimensions as those that the 9mm/.40/.357sig line of pistols use.

Use by Law EnforcementEdit

Four state law enforcement agencies have adopted the .45 G.A.P. as a replacement to their current issue 9×19mm Parabellum (New York) or .40 S&W service handguns (Georgia, South Carolina, and Florida). The New York State Police, Georgia State Patrol, South Carolina Highway Patrol, and Florida Highway Patrol[2] have all adopted the Glock 37 and .45 G.A.P.

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 G.A.P., including some Para-Ordnance M1911s and the Springfield Armory XD, which was actually the first pistol produced in the cartridge. Para has since dropped the G.A.P. Springfield Armory's XD pistol is listed in several different 45 G.A.P. varieties on their web site, but they no longer produce any pistols in that caliber. Only Glock continues to manufacture pistols in the 45 G.A.P. cartridge.

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