Re: .50 GI...Anyone have one?
Wiki...
Performance
The .50GI operates at pressures comparable to the .45 ACP, around 15,000 psi (100 MPa). Interestingly, felt recoil is also similar to the .45 ACP. The .50GI has quickly developed a reputation for accuracy, though this is due in no small part to the extreme precision with which the semi-custom and very expensive Guncrafter pistols are produced. The 300 grain (19 g) JFP (jacketed flatpoint) produces a 25-yard group of 2.24 inches, and the 300-grain JHP (jacketed hollowpoint) and 275-grain JHP produce a 25-yard group of only 1.14 inches.
The penetration and delivered energy of this slower round is about the same as a .40 Smith and Wesson and .45 ACP cartridge. Despite its .50 caliber size, <span style="color: #FF0000">it is a far cry from the .50 Action Express and .500 S&W Magnum in terms of ft·lbs;</span> however, it offers the practical use of a large caliber projectile never before seen in a semiauto handgun. Factory loaded ammunition has an impact force which ranges from .40 Smith and Wesson to lighter .357 Magnum rounds, topping out just below the 500 ft·lb mark. Impact force can be increased with judicious handloading as evidenced by the Guncrafter Industries' website, which has suggested loads that push the cartridge into the realm of the .44 Magnum. Increasing the length of the barrel can also possibly increase velocities with a commensurate increase in ft·lbs of energy.
The cartridge is mainly used in independent law enforcement and personal defense, as its high cost and limited availability hamper wider use. Currently, the only commercial handguns available in this caliber are Guncrafter Industries' own Colt 1911 handgun variants and its Glock 21 / Glock 20 conversion upper.
Ballistics
300 gr (19 g) JFP, 700 ft/s, 350 ft-lbf
275 gr (18 g) JHP, 900 ft/s, 495 ft-lbf
300 gr (19 g) JHP, 860 ft/s, 493 ft-lbf
Switch, I'm thinking nope...