.50 GI
| .50 GI | ||||||||||||||||||||
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A .50 GI next to a .45 ACP cartridge.
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| Type | Handgun | |||||||||||||||||||
| Place of origin | United States | |||||||||||||||||||
| Production history | ||||||||||||||||||||
| Designer | Vic Tibbets / Alex Zimmermann | |||||||||||||||||||
| Designed | 2004 | |||||||||||||||||||
| Manufacturer | Guncrafter Industries | |||||||||||||||||||
| Specifications | ||||||||||||||||||||
| Case type | Rebated (RB), 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) | |||||||||||||||||||
| Ballistic performance | ||||||||||||||||||||
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The .50 GI (12.7×23mmRB) pistol cartridge was developed by Vic Tibbets and 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.
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 slightly shorter than the .45 ACP but is wider. 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.
The .50 GI operates at pressures comparable to the .45 ACP, around 15,000 psi (100 MPa). Felt recoil is not unlike that of the .45 ACP. The .50 GI has developed a reputation for accuracy, though this may be due to the high precision of the semi-custom and very expensive Guncrafter pistols themselves. In one test, the 300 grain (19 g) jacketed flatpoint (JFP) gave a 25-yard group of 2.24 inches, and the 300-grain Jacketed hollow point (JHP) and 275-grain JHP gave a 25-yard group of 2.14 inches.
The penetration in gelatin (but not necessarily the kinetic energy) of the .50 GI is significantly different than the .45 ACP. While it is one of the few examples of the largest caliber projectile (.50) in a semiauto handgun it was purpose built to have a recoil impulse and kinetic energy substantially less than the magnum .50 caliber rounds such as the 50 Action Express (semiautomatic) or .500 S&W Magnum (revolver). Factory loaded ammunition has a kinetic energy of around 500 ft·lb.
In one evaluation the following performance difference was noted between the .45 ACP and the .50 GI: "It actually pounded my steel target with so much force that it knocked the entire 100-pound plate and stand combo hard enough to make it furrow the ground it stood upon.[...]Folks, these .50 calibers really do hit that hard. [The 300 grain TMJ] caused dings in steel targets that normally fracture .40 and .45 cal rounds into so much dust."
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