The Importance of Suppressor Alignment with the Bore

Why spacers, washers, or jam nuts must not be used during suppressor installation

When using a suppressor, it is critically important to ensure perfect concentricity (alignment along a single axis) between its internal bore and the barrel’s bore. Even the slightest misalignment can cause the projectile to clip the internal components of the suppressor—an event known as a baffle strike.

Consequences of Misalignment
The results of misalignment can be severe, ranging from damage or destruction of the internal baffles and end cap to serious safety risks for the shooter.

Even without a direct collision, misalignment significantly affects the flight trajectory (Point of Impact shift). A known example involves an incorrectly installed muzzle device and suppressor that caused rounds to shift approximately 60 cm from the target; once the installation was corrected, the deviation was reduced to ≈5 cm.

Strict alignment is the key to preserving your equipment and ensuring shooting accuracy.

Why Direct Threading is Mandatory

A suppressor must be mounted directly onto the barrel threads without any third-party gaskets or adapters. Any additional element between the barrel and the suppressor can disrupt axial alignment. Below are typical «intermediate» parts—threaded spacers, crush washers, jam nuts, and adapters—and why their use is unacceptable.

Crush Washers and Other Shims: The Risk of Canting

When installing suppressors, the use of any such washers is strictly prohibited.

A crush washer deforms unevenly, causing the threaded device to sit at an angle. Even a tiny deviation tilts the suppressor relative to the bore, drastically increasing the chance of a baffle strike. Even if the tilt is invisible to the eye, tolerances are tight—a bullet passing through a suppressor may have only millimeters of clearance.

Even if the misalignment caused by a washer is not visually apparent, the tolerances are extremely tight—a bullet passing through the suppressor has a clearance of only a few millimeters. Therefore, any deformation of a gasket or shim can shift the suppressor’s axis. Hence the general rule: crush washers must not be used for suppressor mounting under any circumstances.

Jam Nuts: The Danger of Misalignment

While jam nuts are sometimes used instead of shims to time muzzle brakes (DTK) or compensators, this practice is unacceptable for suppressors. Like a washer, a jam nut is an external element on the thread that can compromise alignment.

The problem is that during tightening, the nut may not seat perfectly flush against the suppressor’s internal shoulder. In any thread, there is always a small amount of «play» between the grooves. When you tighten the nut, it can tilt slightly, throwing off the axis. Using a jam nut with a suppressor is an unnecessary risk, especially if used for «floating» installations where the nut is not pressed against the barrel shoulder. If your rifle has a small shoulder area, contact us; we can manufacture a custom solution specifically for your barrel.

Adapters and spacers are a separate category. A threaded adapter is used when the suppressor thread doesn’t match the barrel (e.g., a 1/2″×28 barrel and an M24×1.5 suppressor). A spacer is a short threaded sleeve used to extend the threaded section.

Any such additional element carries the risk of misalignment due to «tolerance stacking»—every junction adds a small margin of error, resulting in a noticeable tilt. Do not «extend» your barrel with extra threaded connections.

When there are no threads at all, shooters often look for clamp-on adapters. Most of these are «garage-made» without proper quality control. In 99% of cases, they will cause a suppressor tilt. We recommend having a proper thread cut in a factory environment instead.

DIY solutions are unacceptable. Attempting to save money here risks damaging your suppressor, your barrel, or in the case of high-power calibers, causing personal injury. Every extra «layer» is a potential source of shift.

Threaded and Collet Adapters

Adapters and spacers are a separate category. A threaded adapter is used when the suppressor thread does not match the barrel thread (for example, the barrel is 1/2″×28 and the suppressor is M24×1.5). A spacer is a short threaded sleeve or ring that extends the threaded section and serves as an intermediate link.

Any such additional element carries the risk of disrupting concentricity due to the accumulation of tolerances. This phenomenon is known as «tolerance stacking» — every connection point adds a slight tolerance or play, which in total results in a noticeable tilt or axial displacement. It is not advisable to «build up» the barrel with extra threaded connections.

When there is no thread at all, people often begin searching for «clamp-on» (collet) adapters. The vast majority of such adapters are manufactured without proper quality control or precise tolerances by «garage» craftsmen. In 99% of cases, such an adapter will cause suppressor misalignment during installation. Instead, contact us — we will cut the appropriate thread under factory conditions.

DIY solutions are unacceptable here! Attempting to save money risks damaging both the sound moderator and the barrel. In the case of high-power calibers, it poses a serious risk of personal injury.

Every additional «layer» between the barrel and the suppressor is a potential source of displacement, so strive to minimize the number of transition parts. The shorter and simpler the path, the more reliably concentricity is maintained.

Indexing: «Muzzle Face» vs. «Shoulder»

Essentially, there are two scenarios for mounting a suppressor:

Shoulder Indexing — the moderator seats against the barrel’s thread shoulder (collar) and is aligned by this specific flat surface.

Muzzle Face Indexing — the device indexes against the muzzle crown, while the threads only serve to pull the device into place.

The geometry of your barrel dictates which option to choose. Quite often, a carbine arrives after a poor threading job where there is virtually no shoulder: the contact area is too narrow, or the chamfers are too deep, leaving nothing to index against. In such cases, «shoulder indexing» becomes a lottery with a high risk of misalignment and bullet clipping. For these barrels, we manufacture custom moderators designed for muzzle face indexing or with a precision collar tailored specifically to your carbine.

A simple rule: first, objectively evaluate the threads (shoulder area, perpendicularity, runout), and then choose the indexing type. If you are unsure — send us photos and measurements, and we will advise you on the correct setup.

It is worth mentioning manual thread cutting in «amateur» conditions separately. Once, a client approached us to select a suppressor for his small-bore rifle. We chose the device, and then it was time to discuss the technical details. When the client stated that his threads were cut to M20x1.5, we were shocked. Those who know the subject immediately understood the problem. Local «handymen» took a die based on the barrel’s outer diameter and cut what was essentially plumbing threads on the rifle! We eventually convinced the client to re-cut the threads to the industry standard for that caliber — 1/2”-28 UNEF.

Summary

When using a threaded mount for a suppressor, it is forbidden to use any third-party parts on the threads, as they disrupt concentricity.

Neither washers (especially crush washers), nor jam nuts, nor threaded adapters/spacers can provide a connection as rigid, level, and concentric as direct threading. Even a minor deviation can lead to serious consequences — from reduced accuracy to the destruction of an expensive device.

To avoid this, the suppressor should be mounted only on clean barrel threads, pressing it tightly against the factory shoulder of the barrel. All auxiliary elements (thread protectors, O-rings, etc.) must be removed before installation. After mounting, always check the alignment visually or by using a bore alignment rod.

High-quality installation without any third-party gaskets or shims is the guarantee of your suppressor’s longevity and stable, accurate shooting.

The general conclusion is clear: a suppressor must be mounted «directly» and without unnecessary intermediate parts, ensuring the most precise alignment with the bore. This is the only way to achieve the safe and effective operation of your sound reduction device.