Is it possible to re-thread a 5/8-24 carbon barrel?

[shields shtr]

I have a few Carbon barrel rifles that were...(custom threaded) for the Thunderbeast Brakes for the thread over brake style TBAC suppressors. By this I mean the threads were "timed" so to speak so when I threaded the brake on they were perfectly timed without the use of the crush washers to align the brake. Interestingly, by doing this for whatever reason it has made other 5/8-24 adapters useless. They will thread on about 3 turns and then a hard stop.

So, can you "erase" the current threads on the barrel and rethread to a "standard" 5/8-24? Obviously, can't cut the carbon barrel down.

 

[Maurygold]

Going to need a picture but I think it’s unusual you would have such little thread engagement

 

[oldrifleman]

I wonder if it was thread for a different pitch. Timing a muzzle brake does not normally change a 5/8x 24 thread.

 

[Supersubes]

I have a few Carbon barrel rifles that were...(custom threaded) for the Thunderbeast Brakes for the thread over brake style TBAC suppressors. By this I mean the threads were "timed" so to speak so when I threaded the brake on they were perfectly timed without the use of the crush washers to align the brake. Interestingly, by doing this for whatever reason it has made other 5/8-24 adapters useless. They will thread on about 3 turns and then a hard stop.

So, can you "erase" the current threads on the barrel and rethread to a "standard" 5/8-24? Obviously, can't cut the carbon barrel down.

Sounds like whoever threaded your barrels was doing a “thread to fit” pitch dimension. It’s not hard for a competent gunsmith to put the barrel back in the lathe and pick up the current thread. He simply shrinks the pitch diameter until the thread is in proper specification.

 

[Raider4044]

Sounds like whoever threaded your barrels was doing a “thread to fit” pitch dimension. It’s not hard for a competent gunsmith to put the barrel back in the lathe and pick up the current thread. He simply shrinks the pitch diameter until the thread is in proper specification.

This…Fairly simple job for any decent smith.

 

[shields shtr]

Thanks All. Lesson learned for me, going to do standard 5/8-24 from now on.

 

[Supersubes]

Thanks All. Lesson learned for me, going to do standard 5/8-24 from now on.

Just to complete your understanding here, threads are divided into classes. In the case of muzzle threads, the classes we see in gun work are 3A and 2A(A is for male threads, B for female threads). These two classes overlap, but 3A can be slightly larger than 2A, but has a smaller tolerance window. Everyone likes to see small tolerances, but there isnt a large distinction here in the case of muzzle threads. A 2A thread would fit more stuff(like a slightly smaller than proper spec muzzle device) and will function just fine. See the chart below for the 3A and 2A pitch diameters for a 5/8-24 thread. The thread is verified using thread ring gauges(Go and no-go). If the Go gauge wont thread on, the thread is too large in pitch diameter, if the No-go will thread on, the thread is too small. Don’t go buy gauges, they're stupidly expensive, just verify the shop is going to adhere to one of these classes and move on.

Some shops call out the class they're adhering to up front, such as Patriot valley arms. See the pic of their muzzle thread drop-down below. Other shops can answer the question if you ask.

Muzzle device manufactures should also be adhering to a class(3B or 2B). Shit happens though, and parts get shipped that are out of spec.

 

[Wannashootit]

If you're able to, mike the OD of the thread tenon.
If the OD is within spec (.616-.625 roughly) you can use a die to cut the minor diameter a bit more to fit your device.

 

[Rubicon Precision]

If you're able to, mike the OD of the thread tenon.
If the OD is within spec (.616-.625 roughly) you can use a die to cut the minor diameter a bit more to fit your device.

I was going to say this, but knew the internets would shit all over me for mentioning a die in a muzzle thread thread.
But in reality, on an established thread, that is likely a thou or two over, you’re not going to make it crooked. The only potential issue would be if the die will thread close enough to the shoulder.

 

[SRPowah]

But in reality, on an established thread, that is likely a thou or two over, you’re not going to make it crooked.

Some Marine out there will be itching to run off to Harbor Freight and challenge your reality...