Smallest barrel to accept 5/8x24 threads w/out shoulder…

[270quest]

Thinking about spinning a 8 twist barrel on the tikka 7 mag to shoot heavier bullets and have a bit heavier/stiffer barrel for a suppressor. Going to finish at 22”.

How much barrel will I need to still get threads on it without the need for a false shoulder?

Was looking at a Bartlien 3B - that’s around .700 at 26” so guessing maybe .710 ish at 22?

The #3 shows .670 at 26”, so even if it’s .680 at 22, not sure that’s enough?

I was set on a carbon barrel but for the price I can get a bartlien right now - steel makes far more financial sense.

Thoughts?

 

[Firestone]

Why not just go 1/2×28 and pick whatever contour you want? Unless you want a heavier barrel

 

[pods8 (Rugged Stitching)]

Recommendations vary but thunderbeast specs as an example want .725” minimum for 5/8-24.

Going too little and you probably have more chance of damaging the minimal shoulder you tighten against.

There are .75” straight contours as an option.

Thunder Beast Arms Corporation [TBAC] | Tech | THREAD SPECIFICATIONS

 

[nphunter]

Just use an adapter and cut it however short you want. I have a Kimber at 16.5” with a super skinny barrel.

 

[Samson7x]

A bart 3b will have enough for 5/8-24 at 22”

I’ve got one threaded with that at 23” and no issues.

 

[SloppyJ]

5/8= 0.625".

Anything extra is shoulder. Divide the remainder by 2 to get your shoulder dimension since that's a diameter. This is assuming the bore is dead dick centered.

A safe bet is .750" finished at your desired length.

 

[HandgunHTR]

I have an X-Caliber barrel that is 0.685 at 21" and is threaded 5/8-24. My DT suppressor (Dead Air Nomad) threads up just fine, stays put, and works great. Unless you are using a wrench to tighten it and using wookie torque, there is an almost 0% chance of damage.

 

[Shortschaf]

My tikka lite barrel is 0.650 diameter at 20"
Too little shoulder for 5/8" threads.

So I did 9/16" threads, and bought the exact adapter that @nphunter linked above. Works great. Can stays tight

But if you aren't into that, agree with @HandgunHTR above that 0.69" is my personal minimum for 5/8" threads

 

[wind gypsy]

Bartlein 3 and 3b taper 0.010” per inch thus at 22” a #3 would be around 0.710”. I’d have no qualms about 5/8” threading in that setup.

 

[khuber84]

Thinking about spinning a 8 twist barrel on the tikka 7 mag to shoot heavier bullets and have a bit heavier/stiffer barrel for a suppressor. Going to finish at 22”.

How much barrel will I need to still get threads on it without the need for a false shoulder?

Was looking at a Bartlien 3B - that’s around .700 at 26” so guessing maybe .710 ish at 22?

The #3 shows .670 at 26”, so even if it’s .680 at 22, not sure that’s enough?

I was set on a carbon barrel but for the price I can get a bartlien right now - steel makes far more financial sense.

Thoughts?

If you're going to run a qd mount for a suppressor, some smith's say it's fine being under 0.700, just rokset it on good and tight. For direct thread, I'd def suggest a 700 diameter or larger. A light palma is actually liger than a Bart 3b, or ace #3. I know an ace #2 or Bart #3 is good to go for threads at 18".

 

[mt100gr.]

My tikka lite barrel is 0.650 diameter at 20"
Too little shoulder for 5/8" threads.

So I did 9/16" threads, and bought the exact adapter that @nphunter linked above. Works great. Can stays tight

But if you aren't into that, agree with @HandgunHTR above that 0.69" is my personal minimum for 5/8" threads

How is the relief cut spacing between the last threads and the shoulder on these adapters? Hard to tell in their pics if there is relief? Thanks!

 

[wapitibob]

How is the relief cut spacing between the last threads and the shoulder on these adapters? Hard to tell in their pics if there is relief? Thanks!

They're minor dia. on the OD. The can mount very likely has enough ID clearance. I know the mount on my DD Lti does; I faced off the mount so it's square with the can bore and only left about .005 chamfer, and it butts up fine.

 

[Shortschaf]

How is the relief cut spacing between the last threads and the shoulder on these adapters? Hard to tell in their pics if there is relief? Thanks!

They're minor dia. on the OD. The can mount very likely has enough ID clearance. I know the mount on my DD Lti does; I faced off the mount so it's square with the can bore and only left about .005 chamfer, and it butts up fine.

My OD at the shoulder is basically major diam.
But the ID of suppressor female threads has clearance.

Mine is a 9/16-24 to 5/6-24 adapter. Wonder if wapitibob's is a 1/2-28 to 5/8-24 adapter, allowing for more material to add a relief there(?)

 

[mt100gr.]

My OD at the shoulder is basically major diam.
But the ID of suppressor female threads has clearance.

Mine is a 9/16-24 to 5/6-24 adapter. Wonder if wapitibob's is a 1/2-28 to 5/8-24 adapter, allowing for more material to add a relief there(?)

Thank you for the pics!

 

[wapitibob]

My OD at the shoulder is basically major diam.
But the ID of suppressor female threads has clearance.

Mine is a 9/16-24 to 5/6-24 adapter. Wonder if wapitibob's is a 1/2-28 to 5/8-24 adapter, allowing for more material to add a relief there(?)

Not sure what I was thinking, yes, barrel threads and/or barrel adapter threads will be thread od all the way up to the shoulder. I have not seen an adapter or barrel thread cut with the relief cut below the thread major. I did specifically ask my smith to cut one on my last barrel but the suppressor mount had enough ID clearance that it wasn't needed.

 

[pods8 (Rugged Stitching)]

I have not seen an adapter or barrel thread cut with the relief cut below the thread major.

Down range products does on their adapter, I haven’t used one yet but it was on my radar:

 

[wapitibob]

Down range products does on their adapter, I haven’t used one yet but it was on my radar:

View attachment 798110

That is a very good looking adapter.

 

[ropeup79]

Just curious what your issue is with 5/8x24 with a threaded collar faced square to the bore? On a custom barrel you could use any contour, even ultra thin, and have them contour the end of the barrel bigger and thread whatever size you want. No collar or adapter needed. Wilson combat does this on their NULA rifles. Unless you just want a heavier contour.

 

[wind gypsy]

Just curious what your issue is with 5/8x24 with a threaded collar faced square to the bore? On a custom barrel you could use any contour, even ultra thin, and have them contour the end of the barrel bigger and thread whatever size you want. No collar or adapter needed. Wilson combat does this on their NULA rifles. Unless you just want a heavier contour.

Main problem is a custom contour can take a real long time if you have to order vs purchasing an on the shelf blank. Otherwise I’d have all custom contours.

 

[Dust Rider]

Down range products does on their adapter, I haven’t used one yet but it was on my radar:

View attachment 798110

I have a few of their adapters. Quality machine work and good price.