.458 SOCOM Ammo
The .458 SOCOM is a large-bore cartridge developed in 2000 at the request of U.S. Special Operations Command personnel who wanted more stopping power than the 5.56 NATO in a platform that fit standard AR-15/M4 lowers. It launches .458-caliber bullets from 250 to 600 grains, with supersonic loads running 2,100–2,300 fps and subsonic loads dropping to 1,000–1,050 fps for suppressed use. The .458 SOCOM is one of the few AR-15 cartridges capable of delivering truly subsonic, hearing-safe suppressed performance alongside heavy supersonic hunting loads — all from the same platform with only an ammunition change.
Read our full .458 SOCOM Buying Guide ↓
.458 SOCOM vs. .450 Bushmaster: Which Big-Bore AR Should You Choose?
The .450 Bushmaster wins on ammunition availability and cost — it’s carried at most sporting goods stores and is significantly cheaper per round. The .458 SOCOM wins on versatility: its bullet weight range (250–600 gr.) is much wider, enabling both flat-shooting supersonic hunting loads and truly subsonic suppressed loads. The .458 SOCOM was explicitly designed for suppressor use; the .450 Bushmaster was designed for hunting. If suppressed shooting is part of your use case, the .458 SOCOM is the better platform. If you want the most widely available ammo for hunting, the .450 Bushmaster is more practical.
.458 SOCOM Suppressed: What Makes It Special
The .458 SOCOM’s subsonic loads — typically 300–600 grain bullets at 1,000–1,050 fps — are genuinely hearing-safe when run through a quality suppressor. The heavy, large-diameter bullet retains significant energy even at subsonic velocities: a 600-grain bullet at 1,000 fps produces nearly 1,300 ft-lbs — more than adequate for close-range terminal performance. Since January 1, 2026, the NFA $200 tax stamp has been eliminated, making the suppressed .458 SOCOM platform more accessible than ever. This combination of subsonic capability and heavy-bullet energy is what separates the .458 SOCOM from most other suppressor-friendly cartridges.
.458 SOCOM Ballistics: Supersonic Hunting Performance
Supersonic .458 SOCOM loads in the 250–350 grain range run 2,100–2,300 fps and deliver 2,400–2,900 ft-lbs of muzzle energy — in the same class as .45-70 Government +P loads. Effective hunting range is 150–200 yards due to the steeply curved trajectory of heavy, large-bore bullets. Within that range, the .458 SOCOM is an extremely effective cartridge for deer, hogs, and black bear. The large frontal diameter and heavy bullets produce impressive wound channels regardless of bullet construction.
Building a .458 SOCOM AR-15
Like other big-bore AR cartridges, the .458 SOCOM uses a standard AR-15 lower with a dedicated upper, bolt carrier group, and magazine. Standard AR-15 magazines work with .458 SOCOM but at reduced capacity — typically 5–10 rounds. The bolt face is enlarged to accommodate the larger case head. Complete .458 SOCOM uppers are available from Tromix (the original developer), CMMG, Wilson Combat, and others. Quality matters more in big-bore AR uppers than in standard 5.56 builds — a quality barrel and properly headspaced bolt are essential for reliable function.
Best .458 SOCOM Ammunition Brands
Underwood Ammunition offers an extensive .458 SOCOM lineup including both supersonic hunting loads and subsonic options. SBR Ammunition and True Velocity also produce quality loads. Buffalo Bore offers premium hunting loads in this caliber. Unlike .450 Bushmaster, .458 SOCOM is not commonly stocked at general sporting goods stores — buying online is the most reliable way to source it in quantity. Given this, buying in bulk when it’s available is a practical strategy for regular shooters.
Shop .458 SOCOM Ammo and Big-Bore AR Platforms at Impact Guns
Browse all rifle ammo at Impact Guns. For other suppressor-optimized cartridges, see our .300 Blackout ammo page. For suppressors, visit our suppressors page. Compare big-bore AR options with our AR-15 rifles page.