Thread pitch for fs.

[monkyboy]

Hello All,
Hoping someone can help. I have a Colt A-2 chambered in 7.62x39. I'm wanting to change the flash suppresser to either an AAC Blackout or Smith Vortex. Does anyone know the thread pitch used on the barrel, or know the best place to get the info?

[Frens]

1/2''x28 TPI is the standard thread on 5.56 barrels...I dont know about the 7.62...

[monkyboy]

Thanks Frenz, I think from what I've found that this might be 1/2x36. I removed the A2 fs but won't know thread pitch for sure till I can bring thread gauge home from work Monday.

[spamsammich]

All of noveskes 7.62 chambered barrels seem to be 5/8x24. Dunno if that helps.

[Seth Harness]

"TPI" just stands for "Threads Per Inch".

What your looking for is the degree of pitch the threads are cut at, correct???

All I find googling is TPI, I dont find any info on thread pitch. You say you have a gage at work, I was going to say that they arent that expensive to buy, Just a friendly "FYI".

Good luck,
Seth H.

[monkyboy]

Seth you're right thread pitch is "TPI". I had gotten anxious in trying to get some things ordered and hoped someone would know about this oddball. I'll bring the thread gauge home and confirm the tread pitch Mon-Tues.

[spamsammich]

Noveske uses Smith Vortexes on their 7.62 builds so I know those are available in 5/8-24. I"m betting on that being the correct thread, however, I still haven't been able to find the thread pitch for the Colt barrel via Google search. Maybe Scott Ryan will be able to tell you.

[monkyboy]

Barrel is .5" in dia. Thread pitch is either going to be 28 or 36, they are very fine.