AR-15 owners will soon have another "point five-oh" option for their rifles: the .50 GI. Before now only 1911 and Glock conversion kits were available for the cartridge.
The .50 GI was born out of the idea that if .40 was better than 9mm, and .45 was better than .40, then .50 must be better then .45. It should not be compared to the .500 S&W, .50 Beowulf or the .50 Action Express as it has much less power. The cartridge is comparable to the .45 ACP +P cartridge, but with a larger diameter bullet.
8" SBR with .50 GI magazine.
Carbine with AR-15 magazines converted to take .50 GI
The .50 GI magazine holds 14 rounds and the AR-15 magazine holds 9 rounds.
The 16" upper will sell for $750 and with one magazine. You can see the contact details of the manufacturer, RMW Xtreme Inc., at the beginning of the below video.
Thanks to Giesler for the link.
Hat Tip: Photos from 475AR @ .50 GI Forum
Guncrafter Industries are selling a .50 GI conversion kit for the the Glock 20/21.

Click to expand the image
The .50 GI round should not be compared to the Desert Eagle’s .50 Action Express or the .500 S&W. It is slightly more powerful than the .45 ACP.
Wikipedia information on the .50 GI:
| .50 GI |
| Type |
Handgun |
| Place of origin |
 United States |
| Production history |
| Designer |
Vic Tibbets / Alex Zimmermann |
| Designed |
2004 |
| Manufacturer |
Guncrafter Industries |
| Specifications |
| Case type |
Rebated, straight |
| Bullet diameter |
.515Â in (13.1Â mm) |
| Neck diameter |
.526Â in (13.4Â mm) |
| Base diameter |
.526Â in (13.4Â mm) |
| Rim diameter |
.480Â in (12.2Â mm) |
| Case length |
.899Â in (22.8Â mm) |
| Overall length |
1.221Â in (31.0Â mm) |
| Ballistic performance |
| Bullet weight/type |
Velocity |
Energy |
| 275Â gr (17.8Â g) JHP |
900Â ft/s (270Â m/s) |
492 ft·lbf (667 J) |
| 300Â gr (19Â g) JHP |
860Â ft/s (260Â m/s) |
493 ft·lbf (668 J) |

The kit will retail for $595.
Hat Tip: Foodpounds