.50 Action Express

.50 Action Express
.50 Action Express round next to a .32 ACP cartridge.
Type	Handgun
Place of origin	United States
Production history
Designer	Evan Whildin, Action Arms
Designed	1988
Specifications
Case type	Rebated rim, straight
Bullet diameter	.500 in (12.7 mm)
Neck diameter	.540 in (13.7 mm)
Base diameter	.547 in (13.9 mm)
Rim diameter	.514 in (13.1 mm)
Rim thickness	.060 in (1.5 mm)
Case length	1.285 in (32.6 mm)
Overall length	1.610 in (40.9 mm)
Primer type	Large pistol
Ballistic performance
Bullet mass/type Velocity Energy 300 gr (19 g) XTP Hornady 1,475 ft/s (450 m/s) 1,449 ft·lbf (1,965 J) 300 gr (19 g) GDHP Speer 1,550 ft/s (470 m/s) 1,600 ft·lbf (2,200 J) 325 gr (21 g) UCHP Speer 1,450 ft/s (440 m/s) 1,517 ft·lbf (2,057 J)
Test barrel length: 6 in (152 mm) Source(s): Accurate Powder Speer

The .50 Action Express (AE, 12.7×33mm) is a very large and powerful American caliber handgun cartridge. It was developed in 1988 by American Evan Whildin of Action Arms. The .50 AE is one of the most powerful pistol cartridges in production.

The Magnum Research Desert Eagle was the first handgun chambered for the .50 AE. The actual cartridge has a .547 inch (13.9 mm) diameter base, with a rebated rim. The rim diameter of the .50 AE is the same as the .44 Remington Magnum cartridge. A Mark XIX Desert Eagle in .50 AE can be converted to .44 with nothing more than a barrel and magazine change. The .357 and .44 Mark VII guns have a smaller frame and can not be converted to .50 AE without the fitting of a Mark XIX slide assembly and a few other miscellaneous parts at the factory. Any Mark XIX Desert Eagle can be converted to .50 AE, but the .357 model will require a new bolt, barrel, and magazine; some hand-loaders turn their rims down to .357 Magnum dimensions, so that only a new barrel and magazine are needed.

The introduction of the .50AE in the US was met with a rocky start. US laws state that non-sporting firearms may not be over 0.500" in bore diameter (measured land to land) to meet Title I regulations. The original .50 Action Express bore diameter was .500" with conventional rifling, but the switch to polygonal rifling on production Desert Eagles allowed the gauge plug to drop through, rendering the gun a destructive device under Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) regulations. Nominal bullet diameter was reduced to the current 0.500 inch (12.7 mm) rather than the original .510". Thus the noticeably tapered case.

Loaded .50 AE ammunition is currently available from CCI Ammunition, Speer, Hornady, and IMI with the latter ammunition being imported into the US by Magnum Research under the "Samson Ultra" trademark. Fired from a standard six-inch Desert Eagle barrel, Speer's 300-grain load produces a muzzle velocity of over 1,500 ft/s, giving a muzzle energy of over 1,500 ft·lb (2,000 J). Fired from a 10-inch barrel, the same load produces a muzzle velocity of over 1,600 ft/s, giving a muzzle energy of nearly 1,800 ft·lb (2,400 J).