458 SOCOM Brass (Large Pistol primer)
1.569 - 1.576 O.A.L
The SOCOM is an awesome cartridge that is basically a long 50AE (O.A.L. of 1.575") with a rebated .308 style head configuration, necked down to utilize a .458" diameter projectiles. It has been chambered in some bolt guns but it's claim to fame is in the AR-15 platform.
