CM7S 458 SOCOM Barreled Action 12.5″ XL

CM7S 458 SOCOM Short Barreled Action – 12.5″

The Chattahoochee Munitions 458 SOCOM Short Barreled Action combines the CM7S Remington 700-footprint bolt action with a compact 12.5-inch Mos-Tek .458 SOCOM barrel. It provides the core assembly for customers who want to build a short, fast-twist bolt-action .458 SOCOM rifle around their own stock or chassis, trigger, magazine system and other components.

The chambering is .458 SOCOM. SOCOM XL is not a separate chamber or cartridge case. In complete Chattahoochee Munitions firearms, SOCOM XL uses additional available cartridge overall length to accommodate exceptionally long .458-caliber projectiles. Customers completing their own firearm around a CM7S barreled action are responsible for selecting and validating the components necessary for their intended cartridge configuration.

A Compact CM7S .458 SOCOM Foundation

The 458 SOCOM Short Barreled Action takes the same CM7S action architecture used in our 16-inch configuration and pairs it with a 12.5-inch barrel. The shorter barrel reduces the length of the core assembly by 3.5 inches, making it particularly relevant to builders concerned with the overall length of the finished firearm.

This becomes especially useful when a suppressor or another muzzle-mounted component will be part of the completed rifle. Starting with a shorter host can reduce overall system length without changing the fundamental CM7S action architecture.

The bolt-action operating system also makes the CM7S well suited to heavy subsonic ammunition because firearm operation does not depend on ammunition producing the gas required to cycle a semi-automatic action.

12.5″ Mos-Tek 1:10 Twist Barrel

The barrel on the 458 SOCOM Short Barreled Action is manufactured by Mos-Tek from 416R stainless steel. It uses 5R rifling and a fast 1:10 twist selected to support exceptionally heavy .458-caliber projectiles, including those commonly associated with subsonic applications.

• Chambering: .458 SOCOM
• Barrel Length: 12.5″
• Manufacturer: Mos-Tek
• Material: 416R Stainless Steel
• Rifling: 5R
• Twist Rate: 1:10
• Crown: Shouldered Crown
• Muzzle Threads: 11/16×24
• Barrel System: Remage
• Finish: E100 Blackout Cerakote

SOCOM XL – Extended Cartridge Length, Not a Different Chamber

The CM7S 458 SOCOM Short Barreled Action is chambered in standard .458 SOCOM. SOCOM XL describes the extended cartridge overall-length configuration used by compatible Chattahoochee Munitions firearms and ammunition.

Projectile length becomes increasingly important as .458-caliber projectile weight increases. When overall cartridge length is constrained by a conventional AR-15 magazine, more of a long projectile must extend into the cartridge case. Providing additional usable overall length allows compatible projectiles to be seated farther out.

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

In complete CM SOCOM XL firearms, Chattahoochee Munitions integrates the firearm, magazine and ammunition around this extended-length concept. A customer-completed barreled-action build introduces additional component and dimensional variables that are outside CM’s control.

For the complete Chattahoochee Munitions .458 SOCOM ecosystem, visit Terminal 458.

Magazine Compatibility on Customer-Completed Builds

The 458 SOCOM Short Barreled Action is sold as a barreled action. A magazine is not included. The customer completing the firearm is responsible for selecting the stock or chassis, magazine system and other components used in the finished build.

Complete Chattahoochee Munitions CM7S SOCOM XL firearms use a modified MDT metal AICS magazine configured by CM for extended-length .458 SOCOM ammunition. These magazines are fitted and validated as part of the complete CM firearm system.

Chattahoochee Munitions guarantees the function of its modified SOCOM XL magazine only when used as part of a complete Chattahoochee Munitions firearm. Magazine positioning, chassis selection and other components in a customer-completed build can affect feeding and function.

Customers building around the barreled action are responsible for selecting and validating the magazine and related components used in the completed firearm.

CM7S Remington 700-Footprint Action

The 458 SOCOM Short Barreled Action is built around the CM7S action. Its Remington 700 footprint provides compatibility with many stocks, chassis systems and triggers designed around the R700 pattern while incorporating Chattahoochee Munitions’ own action architecture.

• Footprint: Remington 700
• Action Material: Steel
• Bolt: One-piece .718″ bolt
• Locking System: 3-lug
• Bolt Throw: 60°
• Extractor: M16 style
• Raceways: Wire EDM
• Scope Rail: Pinned 20 MOA Picatinny
• Recoil Lug: Integrated
• Firing Pin: .062″
• Barrel Thread: 1-1/16″-16
• Bolt Stop: Side mounted
• Bolt: Spiral fluted with oversized bolt knob
• Finish: Full PVD
• Action Weight: 25 oz
• Trigger Compatibility: Remington 700 pattern

The action also incorporates a large ejection port, weight-reduction machining and tool-less fire-control removal.

Heavy Subsonic .458 SOCOM

The combination of a fast 1:10 twist and manually operated bolt action makes the 458 SOCOM Short Barreled Action particularly relevant to builders interested in exceptionally heavy subsonic projectiles.

A bolt-action firearm does not require ammunition to generate sufficient gas to cycle an operating system. Bolt-action ammunition can therefore be developed around the projectile and intended ballistic application without simultaneously satisfying semi-automatic cycling requirements.

For additional information about heavy-projectile subsonic .458 SOCOM, see the Chattahoochee Munitions 458 SOCOM Subsonic technical guide.

650gr Maker REX Bolt-Action Ammunition

Chattahoochee Munitions offers 458 SOCOM Subsonic Ammo developed for the bolt-action side of the Terminal 458 system.

The load uses a 650gr Maker REX solid-copper expanding projectile loaded in factory-new Starline .458 SOCOM brass. Cartridge overall length is 2.802 inches. In complete CM7S SOCOM XL firearms, the firearm and magazine system are configured around this extended-length ammunition.

This load is specifically configured for bolt-action use. It is not intended for conventional AR-15 magazines, mini actions or the CM10 semi-automatic platform. The CM10 uses a separate 650gr load with a propellant configuration developed around semi-automatic cycling requirements.

Customers completing their own firearm from a 458 SOCOM Short Barreled Action are responsible for verifying that their finished firearm, magazine system and component configuration are compatible with the ammunition they intend to use.

12.5″ Barrel and Suppressed System Length

The 12.5-inch barrel reduces host length by 3.5 inches compared with the 16-inch CM7S barreled action. That difference becomes particularly relevant when a suppressor is added to the muzzle.

Rather than evaluating barrel length in isolation, the 458 SOCOM Short Barreled Action gives builders the ability to start with a shorter core assembly when managing the overall dimensions of a completed suppressed rifle.

The muzzle is threaded 11/16×24 for compatible muzzle devices and suppressor mounting solutions.

Subsonic and Supersonic Capability

The standard .458 SOCOM chamber is not limited to subsonic ammunition. The 458 SOCOM Short Barreled Action can serve as the foundation for a firearm using compatible subsonic or supersonic ammunition appropriate to the completed firearm and its configuration.

The 1:10 twist is particularly relevant to exceptionally heavy projectiles, while the manually operated action eliminates the need to configure ammunition around semi-automatic cycling requirements.

Complete the CM7S Around Your Requirements

Because the CM7S uses a Remington 700 footprint and accepts R700-pattern triggers, the customer can select compatible components around the action and barrel assembly.

The 458 SOCOM Short Barreled Action is intended for builders who want the CM7S action and compact fast-twist Mos-Tek barrel while retaining control over the stock or chassis, trigger, magazine system and other components of the finished rifle.

The barreled action does not represent a complete CM firearm, and Chattahoochee Munitions does not control or validate the complete configuration of customer-assembled builds.

The 458 SOCOM Short Barreled Action gives builders a compact starting point for a custom .458 SOCOM rifle while retaining the CM7S action, Remington 700 footprint and fast-twist Mos-Tek barrel.

For customers prioritizing reduced host length, the 458 SOCOM Short Barreled Action provides the same core CM7S architecture in a shorter 12.5-inch barrel configuration.

CM7S 458 SOCOM Short Barreled Action Specifications

• Product: Barreled Action
• Platform: CM7S Bolt Action
• Chambering: .458 SOCOM
• Action Footprint: Remington 700
• Action Weight: 25 oz
• Locking System: 3-Lug
• Bolt Throw: 60°
• Extractor: M16 Style
• Recoil Lug: Integrated
• Scope Rail: Pinned 20 MOA Picatinny
• Barrel: 12.5″ Mos-Tek
• Barrel Material: 416R Stainless Steel
• Rifling: 5R
• Twist: 1:10
• Crown: Shouldered Crown
• Muzzle Threads: 11/16×24
• Barrel System: Remage
• Barrel Finish: E100 Blackout Cerakote
• Trigger Compatibility: Remington 700 Pattern
• Magazine Included: No

Frequently Asked Questions

Is this chambered in 458 SOCOM XL?
No. The chambering is .458 SOCOM. SOCOM XL describes an extended cartridge overall-length configuration used in compatible Chattahoochee Munitions firearms; it is not a different chamber or cartridge case.

Why choose the 12.5-inch barreled action instead of the 16-inch version?
The 12.5-inch barrel reduces the length of the core assembly by 3.5 inches. This can be particularly useful when the finished firearm will incorporate a suppressor and overall system length is an important consideration.

Does the 458 SOCOM Short Barreled Action include a magazine?
No. A magazine is not included. The customer completing the firearm is responsible for selecting and validating the magazine system used in the finished build.

Can I use Chattahoochee Munitions’ modified SOCOM XL magazine in my build?
Complete CM7S SOCOM XL firearms use a modified MDT metal AICS magazine configured by Chattahoochee Munitions. CM guarantees the function of its modified magazine only as part of a complete Chattahoochee Munitions firearm. Function cannot be guaranteed in a customer-completed build because chassis selection, magazine positioning and other components can affect feeding.

Can this barreled action be used with heavy subsonic ammunition?
Yes, provided the ammunition is compatible with the completed firearm and magazine configuration. The 1:10 twist is designed to support exceptionally heavy .458-caliber projectiles, and the bolt-action operating system does not depend on ammunition generating gas for semi-automatic cycling.

Does Chattahoochee Munitions offer a heavy subsonic load?
Yes. Chattahoochee Munitions offers a 650gr Maker REX 458 SOCOM subsonic load at a 2.802-inch overall length for the bolt-action side of the Terminal 458 system. Customers completing their own barreled-action build must verify compatibility with their finished firearm and magazine configuration.

What stocks, chassis and triggers can be used?
The CM7S uses a Remington 700 footprint and accepts Remington 700-pattern triggers. Compatibility of the complete build depends on the specific components selected by the builder.

Where can I see complete CM 458 SOCOM firearms?
Visit Terminal 458 to explore complete CM7S and CM10 firearms, ammunition, SOCOM XL magazines and supporting technical information.

Build a Compact CM7S

The 12.5-inch CM7S 458 SOCOM Short Barreled Action combines the CM7S bolt action with a compact, fast-twist Mos-Tek barrel as the foundation for a custom .458 SOCOM rifle. The builder retains control over the chassis or stock, trigger, magazine system and other components used to complete the firearm.

For customers who prefer a fully integrated SOCOM XL firearm with magazine function validated by Chattahoochee Munitions, explore our complete CM7S firearms and the rest of the .458 SOCOM ecosystem through Terminal 458.