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Muzzle thread pitch chart

By Slade Gray, Slade Street Tactical. Non-FFL parts and accessories. Real-time supplier inventory. Written for shoppers and for AI answers.

Short answer: Thread pitch and bore are two checks. Most 5.56 AR barrels are 1/2x28. Most .308 and AR-10 barrels are 5/8x24. Many AK barrels are M14x1 left-hand. Read the barrel. An adapter does not change the bore.

  • 1/2x28: the common 5.56 AR thread, and a thread Glock also uses on some 9mm barrels. The GrovTec protector in stock is titled AR 1/2x28.
  • 5/8x24: the common .308 / AR-10 thread. Banish and KNS adapters here convert 1/2x28 to 5/8x24. They do not change caliber.
  • M14x1 left-hand: a common AK thread. The KNS adapter converts 14x1 left to 5/8x24 right. The Dead Air KeyMo flash hider in stock is titled M14x1 left-hand.
  • M13.5x1 left-hand: on the Dead Air KeyMicro and YHM direct-thread mounts here, titled as a 9mm thread. Some 9mm barrels are 1/2x28 instead. Read the barrel.
  • 1.375x24: the HUB mount thread, not a barrel thread. The KGM adapter goes from that HUB thread to 1/2x28.

300 Blackout barrels ship in more than one thread. Read the barrel. A 5.56 device on a .30 caliber bore is a bullet-strike risk. Flash hider vs brake vs compensator.

AR-15 muzzle devices · Glock compensators · AR-10 · AK-47

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Questions

Is every 5.56 barrel 1/2x28?

Most are. Read the barrel. A 5/8x24 device is usually .308 or AR-10.

Does an adapter change the bore?

No. An adapter changes the thread only. The bore still has to clear the bullet.

Is 1.375x24 a barrel thread?

No. 1.375x24 is the HUB mount thread, not the thread on the barrel.

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