.45 GAP

.45 G.A.P.
A .45 G.A.P. cartridge.
Type	Pistol
Place of origin	Austria  United States
Service history
In service	2003–present
Production history
Designer	Ernest Durham
Designed	November 2002
Manufacturer	CCI/Speer
Produced	2003–present
Specifications
Case type	Rimless, straight
Bullet diameter	.451 in (11.5 mm)
Case length	.755 in (19.2 mm)
Overall length	1.070 in (27.2 mm)
Ballistic performance
Bullet mass/type Velocity Energy 185 gr (12 g) Gold Dot JHP 1,150 ft/s (350 m/s) 543 ft·lbf (736 J) 200 gr (13 g) Gold Dot JHP 1,050 ft/s (320 m/s) 490 ft·lbf (660 J) 230 gr (15 g) Gold Dot JHP 935 ft/s (285 m/s) 447 ft·lbf (606 J) 230 gr (15 g) FMJ-FP 940 ft/s (290 m/s) 451 ft·lbf (611 J)
Test barrel length: 4.49 in Source(s): DoubleTap Ammo

The .45 G.A.P. (often called the .45 "GAP") pistol cartridge was designed by Ernest Durham, an engineer with CCI/Speer, at the request of firearms manufacturer Glock to provide a cartridge that would equal the power of the .45 ACP, have a stronger case head to reduce the possibility of case neck blowouts, and shorter to fit in a more compact handgun. G.A.P. is an initialism for "Glock Automatic Pistol", and the .45 G.A.P. is the first commercially introduced cartridge identified with Glock.

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) projectiles as does the .45 ACP.

The full-size Glock 37 pistol was introduced by Glock to use the .45 G.A.P. 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 cal round and is flush with the frame. Magazines for the .45 G.A.P. are of the same dimensions as those that the 9×19mm/.40 S&W/.357 SIG line of pistols use.

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 ( South Carolina, and Florida). The New York State Police, South Carolina Highway Patrol, and Florida Highway Patrol have all adopted the Glock 37 and .45 G.A.P.