.458 SOCOM Complete Upper Receivers
AR15Parts.com builds .458 SOCOM complete upper receivers to order for shooters who demand maximum stopping power from the AR-15 platform. Every upper is assembled, headspaced, and function-checked in our shop. Originally developed for US Special Operations Command, the .458 SOCOM pushes .45-caliber projectiles from 250 to 600 grains through a standard AR-15 upper receiver. The result is devastating close-range power that turns your AR-15 lower into a big-bore thumper capable of handling the largest game in North America. Configure your .458 SOCOM upper with your choice of barrel length from 10.5" to 18", handguard, muzzle device, and optional BCG and charging handle.
Why Shooters Choose AR15Parts.com for .458 SOCOM Uppers
Every .458 SOCOM upper is built in-house, headspaced, and inspected. We build each upper to your specifications using quality components designed to handle the cartridge's significant operating pressures. No FFL required.
How to Choose the Right .458 SOCOM Upper
Barrel Length & Gas System
.458 SOCOM uppers are available in 10.5", 12.7", 16", and 18" barrel lengths. Shorter barrels with pistol-length gas create compact, devastating-power platforms. A 16" barrel maximizes velocity while keeping the rifle at legal minimum length without a tax stamp. The 1:14 twist rate stabilizes the full range of .458 SOCOM projectiles.
Complete Upper vs. Barreled Upper
Complete uppers include the dedicated .458 SOCOM BCG and charging handle. The .458 SOCOM requires a dedicated bolt, so a complete upper is strongly recommended for first-time builders.
Key Specifications
Muzzle Velocity: \~1,900 fps (300gr), \~1,050 fps (600gr subsonic) Effective Range: 200-300 yards Barrel Twist: 1:14 Recoil: Heavy, significant felt recoil Platform: Standard AR-15 lower receiver Projectile Range: 250-600 grains
.458 SOCOM Upper Compatibility
The .458 SOCOM uses a dedicated bolt in a standard AR-15 carrier. It feeds from modified single-stack AR-15 magazines (a standard 30-round magazine holds approximately 10 rounds of .458 SOCOM). The upper fits any mil-spec AR-15 lower. Suppressor compatibility is excellent. With heavy 500-600 grain subsonic projectiles, a suppressed .458 SOCOM is remarkably quiet — one of the quietest centerfire rifle setups available.
Best Uses for .458 SOCOM Uppers
The .458 SOCOM delivers maximum stopping power from the AR-15 platform. It is effective on all North American big game including bear, elk, and large hogs at close range. The cartridge's ability to push 600-grain subsonic projectiles makes it one of the most capable suppressed hunting platforms available. For home and property defense applications where maximum barrier penetration and stopping power are priorities, the .458 SOCOM is in a class of its own among AR-15 calibers.
Frequently Asked Questions
What is included in a complete .458 SOCOM upper?
Complete uppers include the upper receiver, barrel, gas system, handguard, muzzle device, dedicated .458 SOCOM BCG, and charging handle — assembled and headspaced.
Will a .458 SOCOM upper fit my AR-15 lower?
Yes. Our .458 SOCOM uppers fit any standard mil-spec AR-15 lower receiver with no modification.
Can I use my 5.56 BCG?
No. The .458 SOCOM requires a dedicated bolt.
What magazines work with .458 SOCOM?
.458 SOCOM feeds from modified single-stack AR-15 magazines. A standard 30-round magazine body holds approximately 10 rounds.
Can I suppress a .458 SOCOM?
Yes. With heavy 500-600gr subsonic loads and a .45-caliber suppressor, the .458 SOCOM is one of the quietest centerfire rifle platforms available.
What is the effective range?
The .458 SOCOM is effective to 200-300 yards. It is designed for maximum energy transfer at close to medium range.
How long does shipping take?
Most in-stock configurations ship within 3-5 business days. Custom builds may take 2-3 weeks. Orders over $99 ship free.
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