458 SOCOM Suppressed Barreled Action with PLACID OTB
The Chattahoochee Munitions 458 SOCOM Suppressed Barreled Action combines the CM7S Remington 700-footprint bolt action, a full 12.5-inch Mos-Tek .458 SOCOM barrel and the titanium PLACID OTB over-the-barrel suppressor system into one purpose-built assembly.
Chambered in .458 SOCOM, the CM7S uses a fast 1:10 twist barrel to support the long, heavy .458-caliber projectiles central to the Chattahoochee Munitions SOCOM XL system. SOCOM XL is not a different chamber. It describes the extended cartridge overall-length configuration used by compatible CM firearms and ammunition.
PLACID OTB was designed and developed by Chattahoochee Munitions around the CM7S platform. Rather than treating suppression as an accessory selected after the barreled action was developed, the system integrates over-the-barrel suppressor volume into the overall CM7S configuration while retaining the full 12.5-inch unported barrel.
The complete 458 SOCOM Suppressed Barreled Action with PLACID OTB weighs 4 lb 15.7 oz.
Explore complete CM7S and CM10 firearms, ammunition, magazines and technical information through Terminal 458.
What’s Included with the 458 SOCOM Suppressed Barreled Action?
The 458 SOCOM Suppressed Barreled Action starts with the CM7S action and a 12.5-inch Mos-Tek .458 SOCOM barrel. Chattahoochee Munitions then integrates the components required for the PLACID OTB suppressor system.
- CM7S steel action with full PVD coating
- 12.5-inch Mos-Tek .458 SOCOM barrel
- 416R stainless barrel construction
- 5R rifling
- 1:10 twist
- Full-length, unported barrel
- PLACID OTB over-the-barrel suppressor system
- Titanium suppressor construction
- .458-caliber suppressor configuration
A trigger, stock or chassis and magazine are not included. These components are selected separately when completing the firearm.
CM7S Remington 700-Footprint Action
At the center of the 458 SOCOM Suppressed Barreled Action is the Chattahoochee Munitions CM7S. The steel action uses a Remington 700 footprint, allowing the finished firearm to be configured around compatible stocks, chassis systems and Remington 700-pattern triggers.
The CM7S uses a three-lug bolt with a 60-degree throw, M16-style extractor and one-piece .718-inch bolt. Wire EDM raceways provide the bolt path, while a pinned 20 MOA Picatinny rail provides the mounting surface for an optic.
CM7S Action Features
- Construction: Steel
- Footprint: Remington 700
- Locking System: Three-Lug
- Bolt Throw: 60°
- Extractor: M16 Style
- Bolt: One-Piece .718″ Bolt
- Recoil Lug: Integrated
- Raceways: Wire EDM
- Scope Rail: Pinned 20 MOA Picatinny
- Firing Pin: .062″
- Action Weight: 25 oz
- Fire Control: Tool-Less Removal
- Trigger Compatibility: Remington 700 Pattern
- Action Thread: 1-1/16″-16
- Bolt Stop: Side Mounted
- Bolt Knob: Oversized
- Bolt Finish: Spiral Fluted
- Action Finish: Full PVD
12.5″ Mos-Tek .458 SOCOM Barrel
The 458 SOCOM Suppressed Barreled Action uses a 12.5-inch Mos-Tek .458 SOCOM barrel manufactured from 416R stainless steel with 5R rifling and a fast 1:10 twist.
- Chambering: .458 SOCOM
- Barrel Length: 12.5″
- Manufacturer: Mos-Tek
- Material: 416R Stainless Steel
- Rifling: 5R
- Twist: 1:10
- Configuration: Unported
- Crown: Shouldered Crown
- Barrel System: Remage
- Finish: E100 Blackout Cerakote
The fast 1:10 twist supports the exceptionally heavy .458-caliber projectiles used in the Terminal 458 subsonic system. The bolt-action operating system also eliminates the requirement for ammunition to generate sufficient gas to cycle a semi-automatic action.
458 SOCOM XL – Extended Cartridge Length
The chamber of the 458 SOCOM Suppressed Barreled Action remains standard .458 SOCOM. SOCOM XL does not describe a longer chamber or a different cartridge case.
Instead, SOCOM XL takes advantage of additional usable cartridge overall length in compatible firearm and magazine configurations. This becomes particularly relevant with exceptionally long .458-caliber projectiles. When overall cartridge length is constrained by a conventional AR-15 magazine, more of a long projectile must extend into the cartridge case. Additional usable overall length allows compatible projectiles to be seated farther out.
The chamber doesn’t get longer. The cartridge gets more room.
Complete Chattahoochee Munitions SOCOM XL firearms integrate the firearm, magazine and ammunition around this extended-length concept. Customer-completed barreled-action builds introduce additional component and dimensional variables that are outside CM’s control.
PLACID OTB – Suppression Designed Around the CM7S
PLACID OTB is the Chattahoochee Munitions-developed over-the-barrel suppressor system designed around the CM7S platform.
An over-the-barrel or reflex suppressor places a portion of its volume around the barrel rather than positioning the entire suppressor beyond the muzzle. That architecture allows the 458 SOCOM Suppressed Barreled Action to retain its full 12.5-inch unported barrel while incorporating substantial suppressor volume around the host.
The .458 SOCOM version uses titanium construction and a caliber-appropriate .458 configuration. The complete PLACID OTB measures 18.25 inches long, 1.5 inches in diameter and weighs 23.6 ounces.
PLACID OTB Specifications
- System: Over-the-Barrel / Reflex
- Overall Length: 18.25″
- Diameter: 1.5″
- Weight: 23.6 oz
- Construction: Titanium
- Caliber Configuration: .458
- Host Platform: CM7S
Full 12.5″ Unported Barrel
The 458 SOCOM Suppressed Barreled Action retains the full 12.5-inch unported Mos-Tek barrel. PLACID OTB achieves its over-the-barrel configuration without requiring barrel porting as part of the suppressor system.
This allows the CM7S to combine its complete 12.5-inch barrel with an over-the-barrel suppressor architecture specifically developed around the action and barrel assembly.
For a builder considering a suppressed .458 SOCOM bolt action, this configuration provides the CM7S action, fast-twist barrel and PLACID OTB system together rather than requiring the suppressor system to be selected independently after the core assembly is configured.
Heavy Subsonic .458 SOCOM
The combination of the CM7S bolt action, 1:10 twist and PLACID OTB makes the 458 SOCOM Suppressed Barreled Action particularly relevant to heavy subsonic .458 SOCOM applications.
A bolt-action firearm does not depend on ammunition generating the gas necessary to operate a semi-automatic action. This allows bolt-action ammunition to be developed around the projectile and intended ballistic application without simultaneously satisfying semi-automatic cycling requirements.
For more 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 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 ammunition is specifically configured for bolt-action use. It is not intended for conventional AR-15 magazines, mini actions or the CM10 semi-automatic platform.
Customers completing their own firearm around this 458 SOCOM Suppressed Barreled Action are responsible for verifying that the finished firearm, magazine system and component configuration are compatible with the ammunition they intend to use.
Magazine Compatibility for Customer-Completed Builds
The 458 SOCOM Suppressed Barreled Action does not include a magazine. The customer completing the firearm is responsible for selecting and validating the magazine system 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.
Chattahoochee Munitions guarantees the function of its modified SOCOM XL magazine only when used as part of a complete Chattahoochee Munitions firearm. Magazine fit, positioning, chassis selection and other components in a customer-completed build can affect feeding and function.
Customers completing a barreled-action build are therefore responsible for selecting and validating the magazine and related components used in the completed firearm.
Complete the CM7S Around Your Requirements
This product combines the CM7S barreled action and PLACID OTB suppressor system but is not a complete rifle. The customer retains control over the stock or chassis, trigger, magazine system and other components used to complete the firearm.
The CM7S Remington 700 footprint provides compatibility with many stocks and chassis systems designed around that footprint, while the action accepts Remington 700-pattern triggers.
The 458 SOCOM Suppressed Barreled Action therefore provides the action, compact fast-twist barrel and integrated suppression system as the core of the build while leaving the final firearm configuration to the customer.
458 SOCOM Suppressed Barreled Action Specifications
- Product: Barreled Action with PLACID OTB
- 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
- Barrel Configuration: Unported
- Barrel System: Remage
- Barrel Finish: E100 Blackout Cerakote
- Suppressor: PLACID OTB
- Suppressor Construction: Titanium
- Suppressor Length: 18.25″
- Suppressor Diameter: 1.5″
- Suppressor Weight: 23.6 oz
- Complete Barreled Action + PLACID OTB Weight: 4 lb 15.7 oz
- Magazine Included: No
458 SOCOM Suppressed Barreled Action FAQs
What is included with the 458 SOCOM Suppressed Barreled Action?
The assembly includes the CM7S action, an installed 12.5-inch 416R stainless Mos-Tek .458 SOCOM barrel and the titanium PLACID OTB suppressor system. A trigger, stock or chassis and magazine are not included.
Is this chambered in 458 SOCOM or 458 SOCOM XL?
The chambering is .458 SOCOM. SOCOM XL describes the extended cartridge overall-length configuration used in compatible Chattahoochee Munitions firearms. It is not a different chamber.
Does this barreled action include a magazine?
No. A magazine is not included. Complete Chattahoochee Munitions CM7S SOCOM XL firearms use a modified MDT metal AICS magazine configured by CM. Chattahoochee Munitions guarantees the function of that magazine only as part of a complete CM firearm; function cannot be guaranteed in customer-completed builds.
Who developed PLACID OTB?
PLACID OTB was designed and developed by Chattahoochee Munitions around the CM7S platform as an over-the-barrel suppressor system.
Is the 12.5″ barrel ported?
No. The .458 SOCOM barrel used in this configuration is a full 12.5-inch unported barrel.
What is an over-the-barrel suppressor?
An over-the-barrel or reflex suppressor places a portion of the suppressor around the barrel rather than positioning the entire suppressor assembly beyond the muzzle. PLACID OTB uses this architecture around the CM7S barrel.
What is PLACID OTB made from?
PLACID OTB uses titanium construction and is configured with caliber-appropriate components for this .458 SOCOM application.
How large is PLACID OTB?
The suppressor system measures 18.25 inches long, has a 1.5-inch diameter and weighs 23.6 ounces.
How much does the complete barreled action with PLACID OTB weigh?
The complete CM7S barreled action with PLACID OTB weighs 4 lb 15.7 oz.
Can I use the CM 650gr subsonic ammunition with this barreled action?
Chattahoochee Munitions offers a 650gr Maker REX bolt-action load at a 2.802-inch overall length for the CM7S side of the Terminal 458 system. Customers completing their own barreled-action build must verify compatibility with the magazine and complete firearm configuration they assemble.
Where can I find complete 458 SOCOM firearms and ammunition?
Visit Terminal 458 to explore complete CM7S and CM10 firearms, bolt-action and semi-automatic ammunition, the SOCOM XL magazine and supporting technical information.
Build Around the CM7S and PLACID OTB
The 458 SOCOM Suppressed Barreled Action combines the CM7S bolt action, 12.5-inch 1:10 twist Mos-Tek barrel and PLACID OTB into a compact core assembly for a custom suppressed .458 SOCOM build.
For customers who want CM to integrate and validate the complete firearm—including the chassis, trigger and SOCOM XL magazine system—complete CM7S configurations are available through Terminal 458.
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