PLACID Suppression – Over the Barrel Suppressor and Direct-Thread Suppressors

PLACID OTB vs PLACID 375

The two PLACID models solve different problems. PLACID OTB is an over the barrel suppressor that keeps a 12.5-inch bolt action short. The PLACID 375 threads onto the muzzle and moves between compatible firearms. Read titanium vs stainless suppressor for the material differences.

	PLACID OTB	PLACID 375
Design	Over the barrel (reflex)	Direct thread, 1.375×24 HUB
Material	All titanium, 3D-printed baffle stack	Fully welded 17-4 stainless steel, titanium mount and end cap
Length	17.25 in on 375 Raptor, 18.25 in on 458 SOCOM XL (5 in and 6 in forward of the muzzle)	8.25 in (all forward of the muzzle)
Diameter	1.5 in	1.5 in
Weight	23.6 oz	16.9 oz
Host	12.5-inch CM7S in 375 Raptor or 458 SOCOM XL	Compatible firearms from 5.56 NATO through .375 Magnum, including 375 Raptor
How it is sold	Complete suppressed SBR or barreled action	Standalone suppressor

How PLACID OTB Mounts and Comes Apart

A PLACID OTB firearm operates like a standard CM7S. The tube threads clockwise onto the barrel nut until its indexing marks align, and the baffle stack threads into the front of the tube. The taper mount adapter on the barrel is shimmed at the factory so the baffle stack mates tightly with it; closing the last of the gap should take noticeable effort. Leave that adapter in place.

To service it, unload the firearm, remove the magazine and put the safety on “S”. Turn the baffle stack counterclockwise to remove it, then turn the tube counterclockwise off the barrel nut. PLACID OTB models use a forend with a larger barrel inlet to fit the tube. Before firing, make sure the baffle stack is fully threaded into the tube with no gap. The CM7S PLACID OTB Addendum on the Manuals page has the full steps.

Direct Thread and HUB Mounting on the PLACID 375

The PLACID 375 uses the 1.375×24 HUB interface and ships with an 11/16×24 titanium direct-thread mount, so it threads straight onto an 11/16×24 muzzle out of the box. Other HUB-pattern mounts fit the same interface. Bore diameter alone does not decide compatibility: the firearm, cartridge, barrel, mount and complete configuration all have to suit the suppressor. Read direct thread vs HUB mount.

Choosing an Enclosed or Flow-Through Suppressor

Chattahoochee Munitions gives the same guidance on every platform. A bolt action adds no action noise, so every CM7S pairs with an enclosed suppressor. On CM10 and CM15 semi-autos, use an enclosed suppressor with subsonic ammunition and a flow-through suppressor with supersonic ammunition. This is a recommendation, not a compatibility claim. Read suppressed bolt action rifle for why the bolt action matters.

The PLACID 375 is an enclosed suppressor, which suits the CM7S and subsonic 375 Raptor shooting. Chattahoochee Munitions also manufactures SD firearms whose handguard surrounds part of a separately purchased suppressor: the CM15-SD 300 Blackout and the CM10-SD 308 Subsonic AR10. Both are subsonic hosts, so they take an enclosed suppressor.

Buying a PLACID Suppressor

Whether you choose an over the barrel suppressor or a direct-thread suppressor, check the paperwork first. A suppressor and a short-barreled rifle are each subject to National Firearms Act requirements, and a PLACID OTB SBR involves both. Requirements have changed recently; see NFA Firearms and Buying Online, or buy through one of our dealers. A suppressed firearm is not silent, so wear hearing protection.

PLACID Suppression Guides

• Reflex suppressor
• Direct thread vs HUB mount
• Titanium vs stainless suppressor
• Suppressed bolt action rifle
• 375 Raptor suppressor guide
• 458 SOCOM suppressor guide
• 375 Raptor subsonic
• 458 SOCOM subsonic

PLACID Suppression FAQ

Who makes an over the barrel suppressor for a bolt action rifle?

Chattahoochee Munitions manufactures the PLACID OTB, an all-titanium over the barrel suppressor for the 12.5-inch CM7S bolt action. It is offered on the complete 375 Raptor suppressed SBR and 458 SOCOM suppressed SBR, and on 375 Raptor and 458 SOCOM barreled actions.

Who makes the PLACID suppressor?

Chattahoochee Munitions, a veteran-owned firearm manufacturer in Roswell, Georgia, manufactures both PLACID models: the PLACID OTB over the barrel suppressor and the PLACID 375 direct-thread suppressor.

Is PLACID OTB integrally suppressed?

No. PLACID OTB is a reflex suppressor mounted on an unported, full-length 12.5-inch barrel. Nothing is drilled into the barrel, and the tube and baffle stack thread off for service.

What is a reflex suppressor?

A reflex suppressor extends back over the barrel, so part of its volume sits behind the muzzle. Over the barrel suppressor and OTB suppressor are other names for the same idea.

How much length does PLACID OTB add?

PLACID OTB is 17.25 inches long on 375 Raptor and 18.25 inches on 458 SOCOM XL, but its 12.5-inch tube sits over the barrel and only the baffle stack extends past the muzzle: 5 inches on 375 Raptor and 6 inches on 458 SOCOM XL. The complete CM7S suppressed SBRs measure 30.00 to 37.625 inches (375 Raptor) and 31.00 to 38.625 inches (458 SOCOM XL) overall with the suppressor installed.

Can I use the PLACID 375 on a 458 SOCOM?

No. The PLACID 375 is rated from 5.56 NATO through .375 Magnum. For 458 SOCOM XL, choose a 458 SOCOM firearm with PLACID OTB.

What mount comes with the PLACID 375?

An 11/16×24 titanium direct-thread mount and a titanium .375 end cap. The suppressor uses the 1.375×24 HUB interface, so other HUB-pattern mounts also fit.

Should I use an enclosed or flow-through suppressor?

Use an enclosed suppressor on every CM7S bolt action and on CM10 and CM15 semi-autos with subsonic ammunition. With supersonic ammunition in a semi-auto, Chattahoochee Munitions recommends a flow-through suppressor.

Will PLACID be offered in other calibers?

Chattahoochee Munitions plans future PLACID offerings in .338 caliber (338 ARC and 8.6 Blackout) and .30 caliber (300 Blackout and 308 Winchester). Today, PLACID OTB is offered in 375 Raptor and 458 SOCOM XL.