Rethread barrel for suppressor

[AKDAVED]

My current barrel is 5/8 28. It needs to be 9/16 24 to have enough shoulder for a can. My question is, can I have the barrel rethreaded over the existing threads, or do I need to have the barrel cut and rethread?

 

[Supersubes]

Yes, that works. The minor diameter of a 5/8 thread is .575, and the major diameter of a 9/16 thread is .562.

 

[Mike Casselton]

Yes, that works. The minor diameter of a 5/8 thread is .575, and the major diameter of a 9/16 thread is .562.

It's a different pitch.

Or did the OP misquote the thread pitch?

 

[JBoomhauer]

It's a different pitch.

Or did the OP misquote the thread pitch?

Yes.
He is saying the larger thread will be completely removed, and have a little material to spare while still meeting the major diameter numbers for the smaller thread.

 

[Mike Casselton]

Yes.
He is saying the larger thread will be completely removed, and have a little material to spare while still meeting the major diameter numbers for the smaller thread.

I see that now that you pointed out out.
Insert image of Homer Simpson backing through the bush...

 

[AKDAVED]

Thanks. More info. I am using a SiCo can with the ASR mount on the break. The can will fit my 35 whelen and 300's. One of my guns was threaded for a break with 5/8-28 threads and the SiCo break is 5/8-24. That barrel is too thin to have that large of thread diameter and hold a can, so I will need to cut it down. SiCo breaks are also in 9/16-24 hence the request to just cut new threads vs cutting the barrel and starting over.

 

[FisherT&C]

You can turn it down to 9/16x24 , turn to 1/2x28 and use a 5/8x24 thread adapter with a .750" shoulder or have the shoulder turned back and pick up the threads and have about 1.25" of 5/8x24 threads and permanently attach a thread protector leaving about .6-.625 of exposed threads. A concentric shoulder can be turned on the protector and have the protector blended to the barrel. A few ways to skin the cat.

 

[Coopsdaddy]

Interested in this process^

 

[AKDAVED]

I have not gone to the gunsmith yet to get it all figured out. I am hoping to cut new threads vs attaching an adapter.

 

[Coopsdaddy]

You can turn it down to 9/16x24 , turn to 1/2x28 and use a 5/8x24 thread adapter with a .750" shoulder or have the shoulder turned back and pick up the threads and have about 1.25" of 5/8x24 threads and permanently attach a thread protector leaving about .6-.625 of exposed threads. A concentric shoulder can be turned on the protector and have the protector blended to the barrel. A few ways to skin the cat.

Will cutting and threading 1/2x28 with a 5/8 adapter with blended shoulder thin the barrel to much vs just threading 9/16x24 with shoulder?
6.5 and 30/06

 

[FisherT&C]

Will cutting and threading 1/2x28 with a 5/8 adapter with blended shoulder thin the barrel to much vs just threading 9/16x24 with shoulder?
6.5 and 30/06

To do a blended shoulder you have to keep it all 5/8x24. Going with 1/2x28 to 5/8 adapter is fine for 6.5 or 30 cal, I do it all the time for hunting rifles; I just do not undercut the threads because the adapter I use is recessed.

It may not be suave but it solves the problem.

 

[Coopsdaddy]

That looks nice!
I’m not well versed on the machining so that’s why I’m asking a lot of questions.
My barrel is .670 at 16.5 inches and .646 at 19 inches.Looking at cutting 17-18 inches.
I just saw were this guy threaded his thin barrel 5/8x24 longer than normal and added a 5/8 threaded peice and machined it to profile.
The advise is much appreciated!

 

[FisherT&C]

That looks nice!
I’m not well versed on the machining so that’s why I’m asking a lot of questions.
My barrel is .670 at 16.5 inches and .646 at 19 inches.Looking at cutting 17-18 inches.
I just saw were this guy threaded his thin barrel 5/8x24 longer than normal and added a 5/8 threaded peice and machined it to profile.
The advise is much appreciated!

Yes, that's the other process I had mentioned; which is a little more work. If it's worth it to you because you prefer the looks of it then that's what you should go with. Both methods get the job done.