.458 SOCOM Ammo

.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.

Frequently Asked Questions: .458 SOCOM

What is .458 SOCOM?
.458 SOCOM was developed in 2000 at the request of US Special Operations Forces who wanted a harder-hitting close-range cartridge compatible with the standard M4/AR-15 platform after the perceived terminal performance limitations of 5.56 NATO in certain engagements. The cartridge fires a .458-inch bullet (the same diameter as .45-70) at subsonic or supersonic velocities from a standard AR-15 lower receiver — only the upper assembly changes. At subsonic velocities with a suppressor, .458 SOCOM is one of the most capable suppressed defensive and hunting configurations available in an AR-15 format.

How does .458 SOCOM compare to .300 Blackout?
Both are large-bore AR-15 calibers optimized for suppressed use with subsonic loads, but at very different scales. .300 Blackout uses a 220gr subsonic bullet at roughly 1,050 fps. .458 SOCOM uses a 300–600gr subsonic bullet at similar velocities — delivering two to four times the projectile mass and dramatically more terminal energy at close range. .300 Blackout is more versatile and has far broader ammunition availability; .458 SOCOM is the choice for maximum terminal effect at close range in a suppressed platform.

Is .458 SOCOM legal for deer hunting?
Yes in most states — and in straight-wall cartridge states, .458 SOCOM qualifies as a straight-wall cartridge, making it legal during those restricted seasons. Its large bullet diameter and energy delivery make it more than adequate for deer, hogs, and black bear at close to medium range. Subsonic loads are hearing-safe through a quality suppressor.

What rifles are available in .458 SOCOM?
.458 SOCOM uses a standard AR-15 lower. Complete uppers and rifles are available from CMMG, Radical Firearms, Wilson Combat, and specialty builders. Magazine capacity is limited by the large case — typically 7–10 rounds in a standard AR-15 lower.

See Also: .300 Blackout Ammo • .450 Bushmaster Ammo • AR-15 Rifles • Suppressors • All Ammunition