Threading lightweight barrel

[AK4900PA]

I have a Tikka T3x Superlite in 300wm that I want to thread for my Griffin Paladin. I'm going to have a couple inches cut off the barrel and have it threaded. Griffin makes the brake attachment in quite a few thread pitches, but as best I can tell the only two that are viable for my situation are the 1/2x28 and 13x0.75.

.308 bore
.63 muzzle diameter

Would you folks suggest the 1/2x28 or 13x0.75?

 

[Emerson0311]

I had a Howa 300PRC with 1/2” threads. Do not recommend. I have a Tikka that would need 1/2” threads due to skinny barrel. I went with a clamp on brake that works great with tight groups downrange; although you would need a clamp on adapter.

 

[spife7980]

I’d probably try the 9/16x24 myself

 

[wind gypsy]

I’d thread it 5/8x24 and have a shoulder added.

 

[R_A_W]

I messaged Griffin and they said to go with 1/2x28.

?

 

[powdahound76]

I would say talk to the gunsmith who you will have do the work.

Some wont do a 1/2 x 28 on a 30 cal barrel.

 

[AK4900PA]

That tapered shoulder is interesting . Gonna have to look into that.

 

[joe777]

Is the barrel diameter still .63 a couple inches back where it will be cut?

 

[AK4900PA]

It's .63 where I want it cut. I believe it's .61 at the muzzle currently.

 

[FuhQ]

I had this done early last year for 2 old sporter barreled Ruger M77 MKII rifles so I could run suppressors. I had my smith thread them small, then custom make two 416r thread adapters from an old barrel he had laying around, that he permanently attached to the barrels (I think he brazed or fluxed them on the barrel threads). Then once cured, he threaded the adapters 5/8-24 bore-centric, and recut the crowns. Turned out great!

 

[wind gypsy]

That tapered shoulder is interesting . Gonna have to look into that.

It is the answer to lightweight barrels if a guy wants larger than 5/8 threads!

To think, i used to consider elaborate fluting or a barrel cut down to nothing only to wrap some decorative carbon and glue around it at $200-$400 premium just to get lightweight with diameter for muzzle threads.. what a waste.

 

[LeftyJason]

I’d thread it 5/8x24 and have a shoulder added.


View attachment 8559518

Little too small. Measured my t3x lite.

Legend: .dia {distance from muzzle} (barrel length)

.616 {0} (24.33)
.620 {1.358} (23)
.630 {2.57} (21.75)
.640 {3.81} (20.5)
.650 {5.05} (19.25)
.660 {6.27} (18.06)
Recommended od for 9/16 shoulder .662 {6.625} (17.7)
0.673 {8.08} (16.25)Beyond this point has to be registered as an SBR
At front of tupperware 0.711 {13.33} (11)
Recommended od for 5/8 0.725 {15} (9.33)

For mine I had it threaded 9/16 with Thunderbeasts face mount brake. It uses the face of the muzzle as the shoulder. That could be done by a gunsmith to a different brake.

 

[wind gypsy]

Little too small. Measured my t3x lite.

Can you elaborate? Too small to go without adding a shoulder yes but that's why i said i'd have a shoulder added. 0.630" is slightly larger than 5/8 major thread diameter. The picture in my post you quoted seems to have a barrel diameter very close to thread major diameter.

 

[LeftyJason]

Can you elaborate? Too small to go without adding a shoulder yes but that's why i said i'd have a shoulder added. 0.630" is slightly larger than 5/8 major thread diameter. The picture in my post you quoted seems to have a barrel diameter very close to thread major diameter.

What stops the shoulder of the added shoulder?

Measuring the picture and doing some quick scaling, the diameter behind the added shoulder is at least 0.640". That means chopping at least 4" of barrel off.
The t3x superlite in 300 win mag, JRAXSL31R10, is a 24.3" fluted barrel. Chopping 4" off gets it into the fluted section for sure.

I work as an aerospace machinist slowly working towards manufacturing engineer. Been cutting threads in all kinds of materials (not gun threads) since 2006.

 

[wind gypsy]

What stops the shoulder of the added shoulder?

Measuring the picture and doing some quick scaling, the diameter behind the added shoulder is at least 0.640". That means chopping at least 4" of barrel off.
The t3x superlite in 300 win mag, JRAXSL31R10, is a 24.3" fluted barrel. Chopping 4" off gets it into the fluted section for sure.

I work as an aerospace machinist slowly working towards manufacturing engineer. Been cutting threads in all kinds of materials (not gun threads) since 2006.

Missed this reply. I'm not sure how the various added shoulders are held in place/indexed against. I've asked before and was told at least in one case the muzzle is threaded a little deeper where the additional shoulder is put and it they are rokset (or similar) in place in addition to being indexed against a small shoulder.

 

[Wannashootit]

No need to over-complicate it.
.630 muzzle diameter > .625, so as long as the barrel OD is concentric "enough" to the bore it will work.

Cut the 5/8" threads to the tenon length needed for the muzzle device + additional for a thread protector.
Screw on the thread protector, red loctite or Rocksett in place. Turn it down/contour/blend and face the end so you have a perfectly square shoulder.