The .458 SOCOM is a moderately large round designed for a specialized upper receiver that can be mounted on any AR-15 pattern lower receiver. The 300-grain round offers a supersonic muzzle velocity of 1,900 ft/s and 2,405 ft⋅lb similar to a light .45-70 but with a much smaller case.

Place of origin United States
Parent case .50 Action Express
Bullet diameter 0.458 in
Neck diameter 0.485 in
Shoulder diameter 0.531 in
Base diameter 0.541 in
Rim diameter 0.473 in
Rim thickness 0.041 in
Case length 1.575 in
Overall length 2.260 in
Rifling twist 1 in 14″ or 1 in 18″
Primer type Large Pistol
Maximum pressure 35,000psi