458 SOCOM XL Barreled Action | CM7S with PLACID OTB

Purpose-Built for Heavy Subsonic Performance

The CM7S .458 SOCOM XL Barreled Action with PLACID OTB is a purpose-built suppressed platform designed around the massive projectile capability of .458 SOCOM XL.

Rather than adapting a conventional rifle and adding a suppressor at the muzzle, Chattahoochee Munitions engineered the barreled action, cartridge, and suppression system to work together as a complete package.

.458 SOCOM XL

.458 SOCOM XL takes the concept behind .458 SOCOM and pushes it into a short-action bolt-gun platform, providing the additional cartridge length required for exceptionally heavy projectiles while eliminating the dimensional constraints imposed by the AR-15 magazine.

With a 2.802″ overall cartridge length, .458 SOCOM XL is designed specifically for short-action bolt guns and heavy subsonic applications.

The result is exactly what TERMINAL 458 was built around:

More projectile. More mass. More authority on target.

PLACID OTB — Integrated Suppression

The PLACID OTB isn’t simply attached to the end of the barrel.

It is engineered around the CM7S action and barrel system.

The proprietary CM7S barrel nut incorporates 1.375×24 HUB threads and supports a 12.5″ titanium reflex tube extending rearward over the barrel. At the muzzle, a 6″ 3D-printed titanium baffle stack indexes on a taper mount and threads directly into the outer reflex tube.

Expanding gases are intentionally vented rearward from the baffle system into the large-volume reflex chamber surrounding the barrel. This makes the entire over-the-barrel volume an active component of the suppression system.

The result is an 18.25″ all-titanium suppression system weighing just 23.6 oz.

PLACID OTB — Over-the-barrel suppression engineered around the CM7S.

One Integrated System

Pairing .458 SOCOM XL with PLACID OTB creates a system specifically designed around the characteristics of very heavy subsonic ammunition.

Instead of hanging the entire suppressor forward of the muzzle, the reflex architecture places a substantial portion of the system back over the barrel. PLACID OTB provides the internal volume demanded by a cartridge moving extremely heavy .458-caliber projectiles while maintaining a package engineered as part of the CM7S barreled action.

The complete CM7S barreled action with PLACID OTB weighs 4 lb 15.7 oz.

This isn’t a conventional suppressed bolt gun.

It’s CM7S + .458 SOCOM XL + PLACID OTB — three components engineered around one objective:

Maximum subsonic capability in an integrated bolt-action platform.

Frequently Asked Questions

What is .458 SOCOM XL?

.458 SOCOM XL is a bolt-action-focused evolution of .458 SOCOM designed around a 2.802″ overall cartridge length. The additional cartridge length allows the use of exceptionally heavy .458-caliber projectiles without the dimensional limitations imposed by the AR-15 magazine.

Can .458 SOCOM XL be used in a standard .458 SOCOM firearm?

No. .458 SOCOM XL is designed specifically for appropriately chambered short-action bolt-action firearms. It should not be used in standard .458 SOCOM firearms, AR-15 platforms, mini actions, or firearms not specifically chambered for .458 SOCOM XL.

Is the CM7S .458 SOCOM XL designed primarily for subsonic ammunition?

Yes. The CM7S .458 SOCOM XL platform is purpose-built around heavy subsonic .458-caliber projectiles and suppressed operation.

What is PLACID OTB?

PLACID OTB is Chattahoochee Munitions’ purpose-built over-the-barrel/reflex suppression system for the CM7S. Instead of placing the entire suppressor forward of the muzzle, a substantial portion of the suppressor extends rearward over the barrel.

Is PLACID OTB just a conventional suppressor mounted to the barrel?

No. PLACID OTB is engineered around the CM7S action and barrel system. Its proprietary CM7S barrel nut provides the mounting interface for the titanium reflex tube, while the muzzle-mounted baffle stack vents expanding gases rearward into the surrounding reflex chamber.

The over-the-barrel volume is therefore an active part of the suppression system, rather than simply an outer sleeve.

How long is the PLACID OTB?

The complete PLACID OTB suppression system is 18.25 inches long. It consists of a 12.5-inch titanium reflex tube section and a 6-inch 3D-printed titanium baffle stack at the muzzle end.

How much does the PLACID OTB weigh?

The complete PLACID OTB system weighs 23.6 oz. and is constructed entirely from titanium.

How much does the complete CM7S barreled action with PLACID OTB weigh?

The complete CM7S barreled action with PLACID OTB weighs 4 lb 15.7 oz.

What mounting system does PLACID OTB use?

PLACID OTB integrates with the CM7S through a proprietary barrel nut featuring 1.375×24 HUB outer threads. The 3D-printed titanium baffle stack indexes at the muzzle using a taper mount and incorporates external 1.375×24 HUB threads to interface with the outer reflex tube.

Why use an over-the-barrel suppressor for .458 SOCOM XL?

Heavy subsonic .458-caliber ammunition produces a substantial volume of expanding gas. The PLACID OTB architecture provides significant internal volume while positioning much of that volume rearward over the barrel rather than placing the entire suppressor forward of the muzzle.

This architecture is particularly well suited to the design objectives of the .458 SOCOM XL CM7S platform.

Is the PLACID OTB removable?

Yes. PLACID OTB is a dedicated suppression system engineered around the CM7S, but its components are removable rather than being permanently integral to the barreled action.

Does the PLACID OTB require an NFA transfer?

Yes. The PLACID OTB is a firearm suppressor and is subject to applicable federal, state, and local laws and transfer requirements.

What makes this different from a conventional suppressed .458 SOCOM bolt gun?

The difference is that the cartridge, CM7S barreled action, and PLACID OTB suppression system were selected and engineered to function as a unified platform.

.458 SOCOM XL provides the cartridge length needed for extremely heavy .458-caliber projectiles. The CM7S provides the short-action bolt platform. PLACID OTB provides a large-volume titanium suppression system built around that barreled action.

CM7S + .458 SOCOM XL + PLACID OTB — one integrated system built for maximum subsonic capability.