CM10 458 SOCOM 12.5″ SBR – Carbon Gray

CM10 458 SOCOM Semi Auto SBR – 12.5″ Carbon Gray

The Chattahoochee Munitions CM10 458 SOCOM Semi Auto SBR brings the CM10 large-frame architecture into a compact 12.5-inch configuration built around heavy .458-caliber projectiles. A fast 1:10 twist barrel, center-feed AICS magazine system, adjustable gas system and adjustable buffer provide the foundation for a purpose-built short-barreled .458 SOCOM platform.

Finished in Carbon Gray Cerakote with Black B5 Systems furniture, the 12.5-inch CM10 also incorporates SOCOM XL capability, allowing compatible extended-length .458 SOCOM ammunition to take advantage of cartridge overall length beyond conventional AR-15 magazine constraints.

A Compact Large-Frame .458 SOCOM Platform

The 458 SOCOM Semi Auto SBR takes a fundamentally different approach from the traditional AR-15 implementation of .458 SOCOM. The CM10 uses a purpose-built large-frame receiver set with an AICS-pattern magazine well and center-feed architecture.

That architecture provides room for the modified MDT metal AICS magazine used with SOCOM XL ammunition while maintaining semi-automatic operation. Combined with the 12.5-inch barrel, the result is a compact CM10 configuration built around the same firearm, magazine and ammunition ecosystem as the 16-inch rifles.

12.5″ Fast-Twist .458 SOCOM Barrel

The 12.5-inch barrel is manufactured from 416R stainless steel with 5R rifling and a fast 1:10 twist. The twist rate supports exceptionally heavy .458-caliber projectiles, making the 458 SOCOM Semi Auto SBR particularly relevant to heavy-projectile and subsonic applications.

• Chambering: .458 SOCOM
• Barrel Length: 12.5″
• Material: 416R Stainless Steel
• Rifling: 5R
• Twist Rate: 1:10
• Muzzle Threads: 11/16×24
• Gas Journal: .875″
• Gas System: Pistol Length
• Barrel Extension: Center Feed
• Finish: Black Cerakote

For additional information about heavy-projectile .458 SOCOM applications, see our guide to 458 SOCOM Subsonic.

SOCOM XL Capability

The CM10 is chambered in .458 SOCOM. SOCOM XL does not represent a different chamber, different cartridge case or proprietary chamber specification.

Instead, SOCOM XL describes the use of additional cartridge overall length made possible by the compatible firearm and magazine architecture.

This becomes important with exceptionally long .458-caliber projectiles. Conventional AR-15 magazine dimensions restrict overall cartridge length, requiring more of a long projectile to extend into the cartridge case. The CM10 architecture provides additional usable cartridge length so compatible projectiles can be seated farther out.

The chamber doesn’t get longer. The cartridge gets more room.

The 458 SOCOM Semi Auto SBR combines that extended-length capability with a compact 12.5-inch barrel and semi-automatic operating system.

Modified AICS Magazine and Center Feeding

The CM10 lower receiver is machined for AICS-pattern magazines rather than conventional AR10 magazines. For SOCOM XL applications, Chattahoochee Munitions uses a 7-round modified MDT metal AICS magazine specifically configured for extended-length .458 SOCOM ammunition.

The magazine feeds along the centerline of the action and works with the center-feed barrel extension. A paddle-style magazine release is positioned forward of the trigger guard.

This magazine architecture gives the 458 SOCOM Semi Auto SBR the cartridge-length space required for the SOCOM XL configuration without changing the .458 SOCOM chamber itself.

CM10-Specific 650gr Semi-Auto Ammunition

Chattahoochee Munitions offers 458 SOCOM Semi Auto Ammo developed specifically around the feeding and operating requirements of the CM10 platform.

The current load uses a 650gr Maker REX solid-copper expanding projectile loaded to a 2.790-inch overall length. Its propellant configuration is selected around the gas requirements necessary for semi-automatic cycling in the CM10.

Specific propellant types, charge weights and other proprietary loading information are not published.

The firearm, modified magazine and compatible ammunition therefore work as parts of the same SOCOM XL system rather than as unrelated components.

Adjustable Gas and Buffer System

A compact big-bore semi-automatic platform benefits from the ability to tune its operating system around different ammunition and suppressor configurations. The CM10 provides adjustment at both the gas system and buffer.

A Superlative Arms .875″ Adjustable Gas Block works with a Melonite pistol-length gas tube. At the rear of the operating system, an Odin Works Adjustable AR10 Buffer provides another point of adjustment.

Together, the adjustable gas and buffer systems give the 458 SOCOM Semi Auto SBR tuning capability when changing ammunition or suppressor configurations.

7075-T6 Billet CM10 Receiver Set

The CM10 upper and lower receivers are machined from 7075-T6 billet aluminum around DPMS Low Profile architecture. The platform maintains compatibility with 16 TPI barrel nuts, DPMS-pattern barrel extensions and compatible large-frame bolt carrier groups while incorporating the CM10-specific AICS magazine system.

• AICS-pattern magazine well
• Center-feed architecture
• Paddle magazine release forward of the trigger guard
• Integral trigger guard
• Weight-reduction machining
• No forward assist
• Fire/Safe markings on both sides
• CM ambidextrous safety
• CM10 pivot and takedown pins

The upper receiver, lower receiver and handguard on this configuration receive Carbon Gray Cerakote.

TriggerTech Duty Trigger

The 458 SOCOM Semi Auto SBR is equipped with a TriggerTech Duty Trigger. Customers can select among three 3.5-pound configurations:

• Single-Stage Flat
• Single-Stage Curved
• Two-Stage Flat

The lower is completed with a CM ambidextrous safety and Black B5 Systems grip.

CM10 Bolt Carrier Group

The CM10 bolt carrier group uses a 9310 steel bolt that is high-pressure tested, magnetic-particle inspected and shot-peened.

• 9310 steel bolt
• HPT / proof tested
• MPI inspected
• Shot-peened
• Nitride bolt, carrier and gas key
• Hardened USGI-spec gas key
• Grade 8 gas-key fasteners
• Mil-Spec gas-key staking
• Tool-steel extractor
• T.E.A. extractor spring
• Black extractor insert
• Mil-Spec Crane O-ring

CM10 Warhammer Ambidextrous Charging Handle

The CM10 Warhammer ambidextrous charging handle is manufactured from 7075 aluminum and provides charging access from either side of the firearm. It was developed with Breek Arms.

11.5″ CM10 LWS M-LOK Handguard

The 12.5-inch 458 SOCOM Semi Auto SBR uses an 11.5-inch CM10 LWS M-LOK handguard manufactured from 6061 aluminum and secured with a steel barrel nut.

• Handguard Length: 11.5″
• Material: 6061 Aluminum
• Steel barrel nut
• Full-length Picatinny top rail
• M-LOK attachment surfaces
• QD sling points at 3 and 9 o’clock
• Carbon Gray Cerakote
• Black B5 Systems rail covers

B5 Systems Furniture and Adjustable Buffer

Black B5 Systems furniture complements the Carbon Gray receiver and handguard. The rifle uses a B5 Systems Bravo Stock, B5 grip and matching rail covers.

The stock is mounted to a CM Mil-Spec buffer tube with a QD end plate and the adjustable Odin Works buffer.

Compact Suppressor-Ready Configuration

The 12.5-inch barrel keeps the host firearm shorter than the 16-inch CM10 configuration before a muzzle device or suppressor is added. For users building around suppressed heavy-projectile ammunition, that shorter barrel can help control the overall length of the complete system.

The fast 1:10 twist, adjustable gas system and adjustable buffer make the 458 SOCOM Semi Auto SBR particularly well suited to configurations where ammunition and suppressor choice can materially change operating-system requirements.

The compact 12.5-inch configuration gives the 458 SOCOM Semi Auto SBR a shorter overall host platform while retaining the fast 1:10 twist and SOCOM XL capability of the CM10 system.

With its modified AICS magazine and center-feed architecture, the 458 SOCOM Semi Auto SBR accommodates extended-length .458 SOCOM ammunition while maintaining semi-automatic operation.

For suppressed and heavy-projectile applications, the 458 SOCOM Semi Auto SBR combines compact dimensions with adjustable gas and buffer systems that allow the operating system to be tuned for the selected configuration.

CM10 458 SOCOM Semi Auto SBR Specifications

• Platform: CM10 Large-Frame Semi-Automatic SBR
• Chambering: .458 SOCOM
• SOCOM XL Capability: Yes
• Barrel: 12.5″ 416R Stainless Steel
• Twist: 1:10
• Rifling: 5R
• Muzzle Threads: 11/16×24
• Gas Journal: .875″
• Gas System: Adjustable / Pistol Length
• Gas Block: Superlative Arms .875″ Adjustable
• Magazine: 7-Round Modified MDT Metal AICS Magazine for SOCOM XL
• Feed Architecture: Center Feed
• Receiver: 7075-T6 Billet Aluminum
• Handguard: 11.5″ CM10 LWS M-LOK
• Trigger: TriggerTech Duty, Selectable Configuration
• Buffer: Odin Works Adjustable AR10 Buffer
• Stock: B5 Systems Bravo
• Furniture: Black B5 Systems
• Finish: Carbon Gray Cerakote

Frequently Asked Questions

Is the CM10 SBR chambered in .458 SOCOM XL?
No. The chamber is .458 SOCOM. SOCOM XL describes the additional cartridge overall-length capability provided by the compatible CM10 firearm and magazine architecture. It is not a different chamber.

Why use a 12.5-inch barrel?
The shorter barrel creates a more compact host than the 16-inch CM10, particularly when a suppressor or other muzzle-mounted component is added. The barrel retains the same fast 1:10 twist used to support exceptionally heavy .458-caliber projectiles.

What handguard does the 12.5-inch CM10 use?
This configuration uses an 11.5-inch CM10 LWS M-LOK handguard manufactured from 6061 aluminum with a steel barrel nut.

What magazine does the CM10 use for SOCOM XL?
The rifle uses a 7-round modified MDT metal AICS magazine specifically configured by Chattahoochee Munitions for extended-length .458 SOCOM ammunition.

Is semi-auto SOCOM XL ammunition available for this SBR?
Yes. Chattahoochee Munitions offers 458 SOCOM Semi Auto Ammo developed specifically around the feeding, gas and cycling requirements of the CM10.

Can the operating system be adjusted?
Yes. The CM10 incorporates an adjustable gas block and adjustable buffer, providing two points of adjustment for different ammunition and suppressor configurations.

Is this firearm an SBR?
Yes. This configuration uses a 12.5-inch barrel and a shoulder stock and is offered as a Short-Barreled Rifle (SBR). Applicable federal, state and local laws and transfer requirements apply.

Where can I learn more about the CM .458 SOCOM ecosystem?
Visit Terminal 458 to explore CM10 and CM7S firearms, SOCOM XL ammunition, magazines and supporting technical information.

Limited Lifetime Warranty

The 458 SOCOM Semi Auto SBR is backed by the Chattahoochee Munitions Limited Lifetime Warranty for the original purchaser, subject to applicable warranty terms and original-configuration requirements.

The CM10 combines a compact 12.5-inch fast-twist barrel, 11.5-inch handguard, center-feed AICS magazine architecture, SOCOM XL capability and adjustable semi-automatic operating system into a purpose-built large-frame SBR. Explore the complete .458 SOCOM family at Terminal 458.