Minimum Barrel OD for threading

[moranna]

Probably been asked many times before so apologies for rookie question.

Plan to purchase first suppressor, a Nomad 30 for multiple rifle calibers. I have 2 older RARs, a 223 and 308. Both have 22" sporter barrels with 0.590 OD at the muzzles

I think I can have the 223 trimmed and threaded for 1/2-28 and use an adaptor to step up to the cans 5/8-24 threads, correct?

For the 308 is that an option also or will I need to cut and recrown barrel for bigger OD to direct thread to the 5/8?

Plan to have a gunsmith perform the 308 work so any recommendations on that would be appreciated.

Thanks

 

[N555]

I think the OD of 1/2x28 threads is about 0.525''.

 

[Blue68f100]

Probably been asked many times before so apologies for rookie question.

Plan to purchase first suppressor, a Nomad 30 for multiple rifle calibers. I have 2 older RARs, a 223 and 308. Both have 22" sporter barrels with 0.590 OD at the muzzles

I think I can have the 223 trimmed and threaded for 1/2-28 and use an adaptor to step up to the cans 5/8-24 threads, correct?

For the 308 is that an option also or will I need to cut and recrown barrel for bigger OD to direct thread to the 5/8?

Plan to have a gunsmith perform the 308 work so any recommendations on that would be appreciated.

Thanks

There is enough meat to use the 1/2"-28 tpi. Nominal OD is 0.5' for the threads for the 223R. Re-crowning should not be needed.

0.590" is enough to go a 15mm metric if you want. Just need to see what adapters are available.

 

[N555]

Friends don't let their friends cut metric threads on muzzles.

 

[BigBlue 94]

OD of 1/2-28 threads is .498" give or take a couple .0005".

For a 5/8 adapter, you need a shoulder to thread the adapter up against. @MachIVshooter can explain it better than I.

Also dont forget the oddball 9/16-24 thread.

 

[moranna]

Thanks guys.

Want to stick with standard 1/2 and 5/8 sizes. Have an inquiry to Dead Air so will see what they recommend.

Think the 223 will have enough shoulder after threading but 308 will have to be shortened to get to minimum OD.

 

[MachIVshooter]

OD of 1/2-28 threads is .498" give or take a couple .0005".

For a 5/8 adapter, you need a shoulder to thread the adapter up against. @MachIVshooter can explain it better than I.

Yep, need a shoulder for any suppressor mounting, .040" is really the minimum width, so barrel OD needs to be .080" larger than thread major.

At .590" OD, 1/2-28 will be fine. Just pay attention to the bore size of a muzzle device with 1/2-28 threads, as a lot of them are meant for .223/5.56 and won't pass a .30 bullet without being opened up.

9/16-24 (.5625") would need a collar to have sufficient shoulder. Mounting options in 9/16-24 are pretty limited.

5/8-24 is a no-go. You need a barrel OD of not less than .635" to be able to get full threads with the typical bore-to-OD runout, and you'll need a collar if your barrel OD is <.705". You may very well be into SBR territory by the time you get to enough meat to support the threads on a 22" sporter that thin at the snout.


1/2-28 is fine for .30 cal sporters. Yes, the walls get a little thin and you'll get slight bore expansion at the tenon (happens with 5/8-24, too). That matters if you're trying to do long range PRS work, but not for a hunting rifle.


Don't put metric threads on it. Zero reason for it, and you'll severely limit your mounting options.