It can be a pain to keep track of all the obscure barrel threads out there - so I figured I'd put what I know here and then build on it over time.  That way it can serve as a reference for quickly locating how your barrel may be threaded. Remember, however, that just because your weapon may be threaded a certain way from the manufacturer - that won't necessarily apply if you have an after-market barrel or have had the barrel threaded yourself. If you find anything in this chart that may be incorrect, please contact us. Ditto if you have some information that you'd like to see added. Some abbreviations that I will use here include:
  • M=Metric (for example - M13.5x1 LH means that the numbers are metric instead of standard.)
  • LH=Left Hand (for example - M13.5x1 LH means the threads are backwards from what you typically expect.  This thread pitch would require righty-loosey, lefty-tighty...)
  • RH=Right Hand (for example - M16x1RH means the threads work how you typically expect (righty-tighty...).  If there is no LH or RH designation - RH is the default.)
Having said all that, here goes:

.22 LR, .22 MAG, .17 HMR

The standard thread for these calibers is 1/2x28.  Please let us know if you are aware of any notable exceptions.

9mm

  • 1/2x28 is the most common thread for 9mm weapons  - both carbine and pistol.
  • H&K weapons use the M13.5x1 LH thread pitch
  • Sig Sauer weapons use the M13.5x1LH thread pitch

.40 S&W

  • 9/16x24 is the most common thread pitch for .40 cal weapons.
  • H&K weapons use the M14.5x1 LH thread pitch

.45

  • .578x28 is the most common thread for .45 cal weapons.
  • H&K USP Tactical uses the M16x1 LH thread pitch
  • H&K Mark 23 (Socom) uses the M16x1 RH thread pitch

5.56mm (.223)

  • AR-15s use the 1/2x28 thread pitch
  • Steyr Aug uses the M13x1 LH thread pitch
  • H&K weapons use the M15x1 thread pitch
  • Ruger Mini uses 9/16x24 thread pitch

7.62mm (.308)

  • 5/8x24 is the most common thread for 7.62mm/.308 weapons
  • Sako TRG uses the M18x1 thread pitch
  • Accuracy International uses the M18x1.5 thread pitch
  • AK-47s use the M14x1LH thread pitch

.338LM

  • 5/8x24 is the most common thread for .338LM weapons
  • Sako TRG uses the M18x1 thread pitch
  • Accuracy International uses the M18x1.5 thread pitch
  • Desert Tactical Arms uses the 3/4x24 thread pitch