.50 GI

.50 GI
A .50 GI next to a .45 ACP cartridge.
Type	Handgun
Place of origin	United States
Production history
Designer	Alex Zimmermann
Designed	2004
Manufacturer	Guncrafter Industries
Produced	2004–present
Specifications
Case type	Rebated, straight
Bullet diameter	.500 in (12.7 mm)
Neck diameter	.526 in (13.4 mm)
Base diameter	.526 in (13.4 mm)
Rim diameter	.480 in (12.2 mm)
Case length	.899 in (22.8 mm)
Overall length	1.221 in (31.0 mm)
Maximum pressure	23,000 psi (160 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 185 gr (12 g) SCHP 1,200 ft/s (370 m/s) 591 ft⋅lbf (801 J) 230 gr (15 g) SCHP 1,000 ft/s (300 m/s) 510 ft⋅lbf (690 J) 275 gr (18 g) JHP 875 ft/s (267 m/s) 468 ft⋅lbf (635 J) 300 gr (19 g) TMJ 700 ft/s (210 m/s) 326 ft⋅lbf (442 J)

The .50 GI (12.7×23mmRB) pistol cartridge was developed by Alex Zimmermann of Guncrafter Industries. The .50 GI was introduced at the 2004 SHOT Show alongside the Guncrafter Industries Model No. 1, a variation of the M1911. The round has a rebated rim that is the same diameter as that of the .45 ACP.^[1][2]

In 2006, Guncrafter Industries introduced its 1911 Model No. 2, which sports a full-length light rail/dust cover and is chambered for the .50 GI cartridge. Both the M1 and the M2 can be fitted with Guncrafter Industries' .45 ACP conversion unit. The .45 ACP magazines hold 8 rounds.

Physically, the .50 GI round is wider than the .45 ACP and slightly longer. The M1 and M2 magazines can hold seven rounds. The Glock conversion can hold eight rounds in the standard magazine and nine with the extended base pad.