//Understanding Suppressor Mounting
HUB LOCKING MOUNT
Field Answers No. 03 — Why Choose a Hub Locking Mount, and How the HUXWRX HUB-QD Adapter Works
A taper to align it. A lock to keep it there. Seat it, lock it, shoot.
// The Short Answer
A taper-only mount depends on the owner to keep it tight. A hub locking mount adds a second, positive step that does not depend on friction alone.
A hub mount threads into the back of any suppressor with the common 1.375 x 24 thread and sets how that suppressor attaches to the rifle. A taper-only mount, covered in Field Answers No. 02, holds on a clean, seated cone and nothing else. A locking mount keeps the taper for alignment and adds a mechanical lock behind it. This sheet uses the HUXWRX HUB-QD Adapter 2.0 as the worked example: the suppressor seats on a taper, threads on left-handed, and is then secured with a lock nut. It is one option among many: most suppressor manufacturers now offer a hub locking mount, so HUXWRX is not the only choice. For a rifle that is fired hard, fired hot, or carried where a tightness check is not practical, that second step is the reason to choose it. It is not the better choice for everyone, and this sheet says where it is not.
// Before You Touch It
Clear the firearm. Every time.
Remove the magazine, lock the action open, and confirm the chamber is empty by eye and by finger before installing, mounting, locking, unlocking or removing anything at the muzzle. A suppressor and adapter that have been fired are hot enough to burn. Let them cool or use a heat-resistant glove or mitt. A lock does not prove alignment; use a rod, and never look down the bore from the muzzle end.
// Verify With Your Manufacturer
Our FAQs are designed to provide general advice. For specific manufacturers, we urge you to consult their specifications and details. Confirm every detail on this sheet with the manufacturer of the parts you are using. The torque figures, thread directions, thread locker guidance and compatibility notes here are published values and general practice, gathered for reference. Manufacturers differ from one another and they revise their instructions. Before you install or fire, check each detail against the current instructions for your specific muzzle device, hub locking mount and suppressor, or contact that manufacturer directly. Where this sheet and the manufacturer disagree, follow the manufacturer.
// Three Things Hold It. Not One.
The taper aligns. The thread direction resists loosening. The lock nut finishes the job.
On a taper-only mount, one feature does everything: the cone aligns the suppressor and the friction in that cone is all that keeps it from backing off. That is simple and it works, but it means retention is only as good as the last time the joint was cleaned and tightened.
A hub locking mount separates those jobs. On the HUXWRX system the suppressor still seats on a taper, so alignment is handled the same way. The mounting thread is left-handed, which the maker describes as tightening the suppressor under firing instead of loosening it. Then a lock nut on the adapter is run down by hand to secure the joint. Each of the three would have to fail for the suppressor to come loose.
One point before the table. This is a proprietary system. The adapter fits a wide range of suppressors, but it mounts only to HUXWRX and OSS QD muzzle devices. That is the price of the lock, and it is the first thing to weigh. The same is true of the hub locking mounts most other manufacturers now offer: each mounts to its own maker’s muzzle devices. The question is not which mount is best. It is which failure you would rather not have.
| The system | Specification |
|---|---|
| Parts | HUXWRX or OSS QD muzzle device on the barrel + HUB-QD Adapter 2.0 in the suppressor |
| Retention | Taper seat + left-hand thread + hand-tightened lock nut |
| Hub thread | 1.375 x 24 into the suppressor |
| Mounting thread | Left-hand — on counter-clockwise, off clockwise |
| Muzzle device to barrel | Approx. 33 ft-lbf (45 N·m), with the maker’s QD wrench |
| Adapter to suppressor | 25 ft-lbf (34 N·m) |
| Suppressor to muzzle device | Hand-tight until firmly seated, then lock nut by hand |
| Lock nut, long-term fit | Wrench until it bottoms out |
| Anti-seize | High-temp anti-seize grease on the mounting and lock nut threads |
| Muzzle devices | HUXWRX and OSS QD only — Muzzle Brake-QD and Flash Hider-QD in 556, 6 and 762 |
| Alignment | Rod check before the first round — see Q 06 |
| What it is not | Not cross-compatible with other mount patterns — see Q 11 |
// Grease The Threads
Use a high-temperature anti-seize grease on the mounting and lock nut threads. Heat and carbon can lock a suppressor joint solid, or gall it: the metal surfaces tear as they seize, damaging the threads on both parts. A thin film of an anti-seize grease made for suppressor threads, such as Breakthrough Clean Technologies Anti-Seize Gun Grease, which its maker rates to 1,800°F, keeps the joint coming apart cleanly. Apply it to the mounting threads of the muzzle device and adapter, and the lock nut threads, wipe off the excess, and keep it out of the bore and off the baffles. Whether it also goes on the taper is your suppressor maker’s call; the HUXWRX manual does not address lubricant. Leave the muzzle-device-to-barrel joint as its maker specifies. It is not a thread locker. Grease also lets a joint reach the same tightness at less torque, so do not add torque to make up for it. Follow your suppressor maker’s guidance where it differs.
// Related Video
// Questions We Get Asked
Why might a hub locking mount be the better option?
Because it answers the one weakness of a taper-only mount, which is that nothing but friction stops the suppressor backing off.
- A positive lock. The lock nut is a separate mechanical step. Retention no longer rests on taper friction alone.
- A thread that works with you. The left-hand mounting thread is described by the maker as tightening under firing, where a conventional thread relies on staying put.
- A state you can see and feel. The lock nut is either run down or it is not, and the adapter carries lock and unlock icons. A taper joint gives no such indication.
- Less dependence on mid-session checks. Heat cycling is what loosens a taper joint. A locked joint is far less sensitive to it.
- Still taper-aligned. The suppressor seats on a cone, so you keep the alignment benefit of a taper mount.
- Still hub-compatible. It threads into any 1.375 x 24 suppressor, so one adapter standard can serve suppressors from several makers.
- Hand-operated in use. Mounting, locking, unlocking and removal are done by hand; a wrench is optional.
What does “locking” actually mean here?
It means there is a second part whose only job is to stop the first joint moving. On this adapter that part is a lock nut: once the suppressor is threaded on and seated, the nut is tightened by hand against it. Other makers achieve the same end with a ratchet, a collar or a latch. The principle is the same in each: the mount is aligned by one feature and retained by another.
Why is the thread left-handed?
So that the forces of firing act to tighten the suppressor on the muzzle device instead of unscrewing it. That is the maker’s stated design intent, not something Second of Ten has measured. The practical consequence for the owner is simple and worth memorizing: the suppressor goes on counter-clockwise and comes off clockwise, the reverse of almost everything else on the rifle.
How is it installed?
Two permanent joints, done once, with every mounting surface clean before you start. Figures are from the maker’s installation manual.
- Clear the firearm and hold the barrel or upper in a proper fixture.
- Fit the QD muzzle device to the barrel. Thread it on and tighten to approximately 33 ft-lbf (45 N·m) using the maker’s QD wrench, with the wrench set at 90° to the torque wrench so the reading is true.
- Remove the suppressor’s factory mount following the suppressor manual, and clean the 1.375 x 24 threads.
- Fit the adapter to the suppressor. Hold the suppressor by its wrench flats in a vise, and torque the adapter to 25 ft-lbf (34 N·m) on its own flats with the maker’s wrench or a 1.5″ socket.
- Thread locker: follow the muzzle device and suppressor makers’ instructions for their own threads.
How do I mount, lock and remove the suppressor?
Three motions on, two off. Check the lock and unlock icons on the adapter whenever you are unsure of direction.
- Wipe the threads and taper surfaces clean on both parts, then put a thin film of high-temperature anti-seize grease on the threads.
- Thread the suppressor on counter-clockwise, by hand, until it is firmly seated.
- Tighten the lock nut by hand in the direction of the lock icon.
- For a long-term fit, use a wrench to run the lock nut down until it bottoms out.
- To remove, let it cool, loosen the lock nut by hand (a wrench if needed), then rotate the suppressor clockwise.
It locks. Do I still need an alignment rod check?
Yes. A lock keeps the suppressor where it seated; it does not prove it seated straight. Before the first round through any new host and suppressor pairing, run a caliber-appropriate rod down the bore on a cleared firearm and confirm it sits centered at the end cap without touching a baffle. Repeat after any change at the muzzle. If it is off-center, do not fire.
Do I still need to check it during a session?
Far less than a taper-only mount, but not never. Confirm the lock nut is run down before the first round and glance at it when you would normally check the rifle over. If a lock nut was only hand-tightened on a rifle that then gets very hot, re-check it once it has cooled. The lock reduces the burden on the owner; it does not remove it.
How does it compare with a taper-only mount, point by point?
Both align on a taper and both fit 1.375 x 24 suppressors. They differ in what they ask of the owner and what they tie the owner to.
- Retention. Taper-only: friction in the cone. Locking: cone, left-hand thread and lock nut.
- Owner checks. Taper-only: after the first few rounds and periodically. Locking: confirm the lock, then occasional.
- Steps to mount. Taper-only: thread on and tighten. Locking: thread on, seat, then lock.
- Moving parts. Taper-only: none. Locking: one, the lock nut.
- Muzzle devices. Taper-only: offered by several makers. Locking: this maker’s QD devices only.
- Thread direction. Taper-only: conventional. Locking: left-handed, which has to be learned.
- Size, weight and cost. A hub locking mount is generally the larger, heavier and more expensive part.
Which muzzle devices and suppressors does it work with?
On the suppressor side, anything with a 1.375 x 24 hub thread. On the rifle side, only HUXWRX and OSS QD muzzle devices: the maker lists the Muzzle Brake-QD and Flash Hider-QD in 556, 6 and 762. It will not mount to a Plan B-pattern device or to any other maker’s mount. The muzzle device and suppressor must both be rated for the caliber being fired.
What changed with the 2.0 version?
As retailers describe it, the 2.0 drops the blast cage extension carried by the original adapter, which makes it the shorter and lighter of the two. The mounting interface and the list of compatible muzzle devices are the same. We have not measured the difference, so we do not quote a figure for it. If you are buying used, confirm which version you are being offered.
What are the trade-offs?
A lock is not free. These are the costs, stated plainly.
- It is proprietary. Every host needs this maker’s QD muzzle device. You are choosing a system, not just a mount.
- The left-hand thread catches people out. Turning it the habitual way tightens what you meant to loosen. Read the icons.
- One more step, one more part. The lock nut has to be run down every time, and it is one more surface for carbon to reach.
- A forgotten lock is a taper-only mount. The advantage exists only when the nut is actually tightened.
- Size, weight and cost. A hub locking mount is a larger, more complex part than a plain taper mount and is priced accordingly.
- Limited muzzle device range. The listed devices cover 556, 6 and 762. Other bores and thread pitches may not be served.
- Tools on installation. The published procedure uses the maker’s own wrenches for both permanent joints.
When is a plain taper mount still the right choice?
When simplicity, weight and freedom to mix makers matter more to you than a secondary lock. A bolt gun or a rifle fired at a measured pace gives a taper joint little reason to loosen, and the owner is in a position to check it. A taper-only mount also makes sense if you already own several hosts fitted with that pattern. See Field Answers No. 02.
Is HUXWRX the only hub locking mount?
No. Most suppressor manufacturers now offer a hub locking mount, using a ratchet, a collar or a latch in place of a lock nut. Because the 1.375 x 24 hub is shared, one maker’s adapter will usually fit another maker’s suppressor. The reasoning on this sheet applies to all of them. The torque figures and thread direction here are specific to the HUXWRX adapter; for any other mount, use its own instructions.
What maintenance does it need?
Slightly more than a plain taper mount, because there is a moving part to keep free.
- Clean the threads and taper surfaces on the muzzle device and inside the adapter after each session.
- Renew the anti-seize grease on the mounting and lock nut threads once they are clean, so carbon cannot lock or gall them.
- Keep the lock nut turning freely. Brush carbon from its threads; a nut that binds will not run down fully.
- Inspect the taper surfaces for dings or galling. Damage there affects alignment; do not shoot on a damaged taper.
- If the adapter backs out of the suppressor, clean both threads and re-torque it to the maker’s figure.
- Re-check alignment after any work at the muzzle.
// What A Hub Locking Mount Does Not Do
It keeps a seated suppressor seated. It does not seat it for you.
- It does not lock itself. The lock nut has to be tightened every time. See Q 05.
- It does not prove alignment. A locked suppressor on a misaligned muzzle is still misaligned. See Q 06.
- It does not correct a barrel problem. No mount can fix muzzle threads that are not concentric with the bore.
- It is not universal, and it is not the only one. It mounts only to this maker’s QD muzzle devices, and bore size has to match the caliber. Other makers offer their own hub locking mounts. See Q 09 and Q 13.
- It does not make a taper-only mount wrong. Both are sound designs that ask different things of the owner. See Q 12.
- This sheet is not your manual. The instructions supplied with your muzzle device, adapter and suppressor are the controlling documents. HUXWRX, OSS, HUB-QD, VENTUM and Plan B are names or marks of their respective owners; Second of Ten is not affiliated with those companies. Nothing here is legal advice regarding suppressor ownership or use.
// Keep A Record
Write down the combination you verified: the host, the muzzle device, the adapter and its version, the suppressor, the torque you used on each permanent joint, and the date the alignment rod passed clean. If the suppressor moves to another host or anything changes at the muzzle, it is a new combination and it gets its own rod check and its own line in the record.
// Where To Find Them
Second of Ten stocks the HUXWRX HUB-QD Adapter, along with a wide selection of mounting devices from various manufacturers. For more information or availability, visit our retail site, www.gundaddy.com, your one-stop source for all your firearms needs and accessories.
Aligned by the taper. Held by the lock. Checked by you.