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. Complete firearms and uppers are available from www.wilsoncombat.com , www.teppojutsu.com or call (832) 524-8100 or www.rockriverarms.com or call (866) 980-7625. Dies are available from most major manufacturers.