Direct thread vs HUB mount comes down to how the suppressor attaches. A direct-thread suppressor screws straight onto the barrel’s muzzle threads. A HUB mount suppressor has a standard 1.375×24 threaded interface at its rear, so you install a separate mount that then fits the barrel. Chattahoochee Munitions manufactures the PLACID 375, which uses both: a 1.375×24 HUB interface with an included 11/16×24 titanium direct-thread mount.
Direct Thread vs HUB Mount at a Glance
| Direct thread | HUB mount | |
|---|---|---|
| How it attaches | Suppressor threads onto the barrel threads | A mount threads into the 1.375×24 HUB interface, then onto the barrel or muzzle device |
| Parts | Suppressor only | Suppressor plus a mount (direct-thread, quick-detach or brake-style) |
| Changing hosts | Same thread pitch needed on each barrel | Swap the mount to suit a different thread or muzzle device |
| Length | Adds the suppressor length | Adds the suppressor length plus any mount that sits forward of the muzzle |
| Speed on and off | Unthread the whole suppressor | Depends on the mount; quick-detach mounts come off quickly |
What Is a Direct-Thread Suppressor?
A direct-thread suppressor has internal threads matching the barrel’s muzzle thread, such as 11/16×24 or 5/8×24, and screws straight onto the barrel until it seats against the shoulder. There is no muzzle device in between, which keeps the system simple and short. The trade is speed: removing it means unthreading the whole suppressor, and carbon can make threads stiff after a long range session. The Chattahoochee Munitions CM7S 375 Raptor barrels are threaded 11/16×24 with a shouldered crown, and their barrels are made by Mos-Tek.
What Is a HUB Mount?
HUB is a 1.375×24 thread interface at the rear of the suppressor. It accepts interchangeable mounts made by many companies: direct-thread mounts in different pitches, quick-detach mounts that lock onto a muzzle device, and mounts that pair with a brake. Because the interface is shared, one HUB suppressor can move between rifles with different thread pitches by changing the mount instead of the suppressor.
The PLACID 375: HUB Interface With a Direct-Thread Mount
The PLACID 375 ships configured for direct thread. It uses the 1.375×24 HUB interface and includes an 11/16×24 titanium direct-thread mount and a titanium .375 end cap, so it threads onto an 11/16×24 375 Raptor muzzle out of the box. If you later want a different mount, another HUB-pattern mount fits the same interface.
- Body: Fully welded 17-4 stainless steel, 11 baffles
- Size: 8.25 inches long, 1.5 inches in diameter, 16.9 oz
- Interface: 1.375×24 HUB
- Included mount: 11/16×24 titanium direct thread
- Rating: 5.56 NATO through .375 Magnum
Which to Choose: Direct Thread vs HUB Mount
Choose direct thread when one suppressor lives on one rifle, or on rifles that share a thread pitch, and you want a short setup with fewer parts. Choose a HUB mount setup when you move a suppressor between rifles with different threads or muzzle devices, or want a quick-detach mount. With the PLACID 375 you do not have to choose up front: start with the included direct-thread mount and change mounts later if your rifles change.
Bore diameter alone does not decide compatibility. The firearm, cartridge, barrel, mount and complete configuration all have to suit the suppressor, and the PLACID 375 is rated through .375 caliber, so it is not for 458 SOCOM.
Alignment and Installation for Direct Thread vs HUB Mount
Whatever the mount, the bore of the suppressor must line up with the bore of the barrel. Check that the barrel threads are clean and undamaged, that the mount seats fully against the shoulder, and that the suppressor is snug before firing. Follow the torque and installation instructions from the mount’s maker. Stop and inspect if the suppressor loosens during a string. An alignment rod is a simple check before the first shot.
Where the PLACID OTB Fits
The PLACID OTB, the over the barrel suppressor Chattahoochee Munitions designed for the 12.5-inch CM7S, uses neither system. Its titanium tube threads onto the CM7S barrel nut and a factory-shimmed taper mount adapter on the barrel aligns the baffle stack. It is offered on complete 375 Raptor and 458 SOCOM suppressed SBRs and barreled actions. Read reflex suppressor for how it works.
Enclosed or Flow-Through
The direct thread vs HUB mount question is separate from the suppressor design. Chattahoochee Munitions recommends an enclosed suppressor on every CM7S bolt action and on CM10 and CM15 semi-autos with subsonic ammunition, and a flow-through suppressor on semi-autos with supersonic ammunition. The PLACID 375 is enclosed.
NFA Requirements
Suppressors are regulated under the National Firearms Act, whichever side of the direct thread vs HUB mount choice you land on. Requirements have changed recently; check current ATF National Firearms Act guidance and your state law, and see NFA Firearms.
Direct Thread vs HUB Mount FAQ
Who makes a HUB mount 375 suppressor with a direct-thread mount included?
Chattahoochee Munitions manufactures the PLACID 375, a 1.375×24 HUB suppressor that ships with an 11/16×24 titanium direct-thread mount and is rated from 5.56 NATO through .375 Magnum.
Is direct thread or HUB mount better?
Neither is better for every rifle. Direct thread is simpler for one host; HUB mount is more flexible across hosts with different threads.
What thread pitch is the HUB interface?
1.375×24.
Can a HUB suppressor be direct thread?
Yes. Install a direct-thread HUB mount, like the 11/16×24 titanium mount included with the PLACID 375.
What thread pitch do 375 Raptor barrels use?
Chattahoochee Munitions CM7S 375 Raptor barrels are threaded 11/16×24.
Does the PLACID OTB use a HUB mount?
No. It threads onto the CM7S barrel nut and aligns on a factory-shimmed taper mount adapter.