Thread pitch is the size and spacing of the threads on your muzzle. Your muzzle device or silencer mount has to match it exactly. This chart lists the most common factory thread for each cartridge and platform, plus the exceptions that catch people.
People often search for thread pitch by caliber. Caliber is the bore diameter, and a cartridge is the specific round, like .308 Win. The charts below list each cartridge by name.
These are conventions, not rules. Barrel makers do not all agree, so confirm with the manufacturer's spec or measure your barrel before you order.
Quick answers
- 5.56 / .223 AR-15: 1/2-28
- .308, 6.5 Creedmoor, .300 Blackout: 5/8-24
- 9mm Luger pistol, US-market barrel: 1/2-28
- .45 ACP: .578-28
- AK-47 / AKM: M14x1 left-hand
Every LPM flash hider and muzzle brake is made in both 1/2-28 and 5/8-24. Shop muzzle devices
Jump to: AR-15 and rimfire | AR-10 and bolt action | Straight-wall and big bore | AK | Pistol | Lever action and others | Thread vs. bore | How to measure | What fits LPM devices | FAQ
In every chart, bold marks the two threads LPM muzzle devices are made in.
AR-15 and rimfire thread pitch chart
| Cartridge | Most common thread | Exceptions and notes |
|---|---|---|
| .223 Rem / 5.56 NATO | 1/2-28 | The AR-15 standard. |
| .22 LR | 1/2-28 | Some older Savage and CZ rimfires use 1/2-20. |
| .17 HMR / .22 WMR | 1/2-28 | |
| .224 Valkyrie | 1/2-28 | |
| .300 Blackout | 5/8-24 | |
| 7.62x39 (AR-15) | 5/8-24 | AK-pattern rifles are different. See the AK chart. |
| 6.5 Grendel | 5/8-24 | |
| 6mm ARC | 5/8-24 | |
| 6.8 SPC | 5/8-24 | |
| 9mm Luger (AR-9 and PCC) | 1/2-28 | Also 1/2-36 on Colt-pattern and older CMMG barrels, 5/8-24 on Wilson Combat, and M13.5x1 LH on the SIG MPX. Check yours. |
| 5.7x28mm carbine | 1/2-28 | FN PS90 barrels are M12x1 LH. |
AR-10 and bolt action thread pitch chart
| Cartridge | Most common thread | Exceptions and notes |
|---|---|---|
| .308 Win / 7.62 NATO | 5/8-24 | Springfield M1A is .595-32. KAC SR-25 is 3/4-24. Some Sako and Accuracy International rifles use metric threads. |
| 6.5 Creedmoor | 5/8-24 | Some ultralight hunting rifles, such as the Howa Super Lite, use 1/2-28. |
| 6mm Creedmoor | 5/8-24 | |
| 6.5 PRC / 7mm PRC / .300 PRC | 5/8-24 | |
| .300 Win Mag | 5/8-24 | |
| .338 Lapua Magnum | 5/8-24 or 3/4-24 | Split by manufacturer. Check yours. |
| 8.6 Blackout | 5/8-24 or M18x1.5 | Split by manufacturer. Check yours. |
Straight-wall and big bore thread pitch chart
There is less agreement here than anywhere else. Check your barrel before you buy anything.
| Cartridge | Most common thread | Exceptions and notes |
|---|---|---|
| 350 Legend | No standard | 1/2-28, 5/8-24, and 11/16-24 are all used on factory rifles. |
| 400 Legend | 11/16-24 | |
| 450 Bushmaster | 11/16-24 | Some barrels use 5/8-32. |
| .458 SOCOM | 5/8-32 or 11/16-24 | Split by manufacturer. |
| .50 Beowulf | 49/64-20 |
AK thread pitch chart
| Rifle | Most common thread | Exceptions and notes |
|---|---|---|
| AK-47 / AKM (7.62x39) | M14x1 LH | Left-hand thread. Yugo M92 and M85 use M26x1.5 LH. |
| AK-74 (5.45x39) | M24x1.5 RH | Also found on some 7.62x39 rifles, including some Arsenal models. |
Pistol thread pitch chart
| Cartridge | Most common thread | Exceptions and notes |
|---|---|---|
| 9mm Luger | 1/2-28 | HK and many European-market barrels use M13.5x1 LH. |
| .40 S&W | 9/16-24 | Common on aftermarket barrels. HK and Glock factory barrels use metric left-hand threads. |
| 10mm Auto | .578-28 | Some aftermarket barrels use 9/16-24. |
| .45 ACP | .578-28 | HK USP45 Tactical and HK45 Tactical use M16x1 LH. |
| .22 LR | 1/2-28 | The Glock 44 threaded barrel is M9x0.75 and uses an adapter. |
Lever action and other rifles
| Rifle | Most common thread | Exceptions and notes |
|---|---|---|
| .30-30 lever action | 5/8-24 | |
| .357 Magnum lever action | 1/2-28 (Marlin 1894) | Henry X Models are 5/8-24. |
| .44 Magnum lever action | 5/8-24 | |
| .45-70 lever action | 11/16-24 (Marlin 1895) | Henry X Models are 5/8-24. |
| Springfield M1A / M14 | .595-32 | |
| Steyr AUG (5.56) | 1/2-28 on current US rifles | Older barrels are M13x1 LH. |
Same thread does not mean same bore
Thread pitch tells you what screws on. It does not tell you what is safe to shoot through it. Cartridges with very different bullet diameters share a thread:
- 1/2-28 is used on .22 LR, 5.56 NATO, 9mm Luger, and .357 Magnum.
- 5/8-24 is used on everything from 6mm ARC to .44 Magnum, and on some .45-70 rifles.
A muzzle device or silencer can thread on perfectly and still get struck by the bullet if its bore is too small. A 9mm bullet is .355" across. It will not clear a .30 caliber bore.
Check the bore of the device against your bullet diameter every time:
- Eclipse, Eclipse-L, and Liberty Bell: .30 caliber bore. For .22 through .30 caliber bullets.
- Baby Bell: .395" bore. For 9mm (.355") and smaller bullets.
- Silencers: every LPM silencer lists a caliber rating on its product page, up to .375 caliber on our .38 big bore models.
Then confirm alignment with a bore alignment rod before you fire.
How to read a thread callout
- 1/2-28 means a 1/2" diameter with 28 threads per inch. You will also see it written 1/2x28 or 1/2"-28. Same thread.
- .578-28 works the same way. Sizes with no clean fraction are written as decimals.
- M14x1 is metric: a 14 mm diameter with 1 mm between threads.
- LH means left-hand. It tightens counterclockwise. If there is no LH, the thread is right-hand.
How to check your barrel's thread pitch
- Look it up. The manufacturer's spec for your exact model is the best source.
- Measure the diameter. Put calipers across the outside of the threads and compare to the table below. Real threads measure a few thousandths under these numbers.
- Check the pitch. Use a thread pitch gauge. It is the only way to tell 5/8-24 from 5/8-32, which share a diameter.
- Check the direction. If a right-hand device will not start, you may have a left-hand thread.
| Thread | Nominal diameter |
|---|---|
| 1/2-28 | .500" |
| M13.5x1 | .531" |
| M14x1 | .551" |
| 9/16-24 | .563" |
| .578-28 | .578" |
| 5/8-24 and 5/8-32 | .625" |
| 11/16-24 | .688" |
| M18x1.5 | .709" |
| 3/4-24 | .750" |
| M24x1.5 | .945" |
M14x1 and 9/16-24 are only about .012" apart, so do not go by eye. If a device binds in the first turn or two, stop. Close is not a fit.
Which LPM devices fit your barrel
| Your barrel thread | What fits |
|---|---|
| 1/2-28 | Any LPM muzzle device in 1/2-28. To run a 5/8-24 device or silencer, add the 1/2-28 to 5/8-24 Thread Adapter. It adds only .19". |
| 5/8-24 | Any LPM muzzle device in 5/8-24. |
| Anything else | We do not make devices in other threads. Use a device made for your thread. |
Thread is only half of it. Match the bore to your caliber too, as covered above.
Pick by job
- Best for general use: Eclipse flash hider (1.7"). It also serves as a sacrificial blast baffle for your silencer.
- Best for flash reduction: Eclipse-L flash hider (2.1"). Not compatible with Q silencers.
- Best for recoil: Liberty Bell muzzle brake (1.7", .30 caliber bore).
- Best for 9mm: Baby Bell muzzle brake (1.1", .395" bore).
- Best for 13.7" and 14.5" barrels: Eclipse 13.7" or Eclipse 14.5" Pin and Weld. Both finish at 16.1". The 13.7" version is not compatible with Q silencers. See 13.7" vs 14.5" Pin and Weld.
Every LPM flash hider and brake has a .900"-24 outer thread for QD mounts like the Rearden Atlas GEN 2 and Q Plan-B. A .900"-24 Thread Protector covers it when the silencer is off.
Mounting an LPM silencer
Every LPM centerfire silencer has a 1.375"-24 HUB rear thread. Mount it direct with a Rearden Ti Direct Thread Adapter in 1/2-28 or 5/8-24, or go quick detach with the Atlas GEN 2 and a muzzle device on each rifle. The full chart is on our Mount Compatibility Guide. Not sure which silencer suits your rifle? Try Find Your Silencer or browse QD silencers.
Thread pitch FAQ
What thread pitch is an AR-15?
1/2-28 for 5.56 and .223. Most other AR-15 cartridges, including .300 Blackout, 7.62x39, 6.5 Grendel, and 6mm ARC, use 5/8-24.
What thread pitch is a .308 or 6.5 Creedmoor?
5/8-24 on most factory rifles. A few ultralight hunting rifles and some European rifles are exceptions, so check your spec.
What thread pitch is a 9mm?
1/2-28 on most US-market pistol barrels. HK and many European-market barrels use M13.5x1 left-hand. 9mm ARs are usually 1/2-28, but 1/2-36 and 5/8-24 are both out there.
Is 1/2-28 the same as 1/2x28?
Yes. The dash and the x are two ways of writing the same thread.
Can I run a 5/8-24 muzzle device on a 1/2-28 barrel?
Yes, with our 1/2-28 to 5/8-24 Thread Adapter. Make sure the bore of the device suits your caliber. More in 1/2-28 vs 5/8-24: A Thread Pitch Guide.
Do I need a crush washer?
Not under a silencer mount. Every LPM device has 360-degree ports, so there is nothing to time. If you time one for looks, use quality shims, never a crush washer. Torque values are in our torque guide.
Keep reading
- 1/2-28 vs 5/8-24: A Thread Pitch Guide
- Which LPM Muzzle Devices Fit Your Mount?
- Torque Specs for LPM Muzzle Devices and Mounts
- Manuals and guides
Thread data comes from manufacturer specifications and was last reviewed in November 2026. Manufacturers change specs. Always verify your own barrel before you buy or install anything.
Torque Specs for LPM Muzzle Devices and Mounts