Tech Question on Barrel Nuts...

[tobnpr]

Just for the fun of it, I'm replacing a milsurp barrel with a new one as a nutted "prefit".
Barrel is a straight contour- tenon thread is .977-16 tpi.
I had started to make a nut for it, then had a lightbulb moment (maybe)- that's awfully close to the 1"-16 tpi of Sakos and Rugers.

Class 2, 1"-16 major is .989-.998, which means I'm between .009 and .018 smaller than the Tikka/Ruger.
.009 sounds a whole lot better than .018, but I have no idea where in that range Tikka and Ruger (and the aftermarket prefits) actually cut their barrels.

Would the Tikka/Ruger nut be too sloppy a thread fit on a .977 tenon to function correctly (even with Rocksett)?

 

[Dusty Stevens]

If you have the action in hand and are able to make a nut why would you build a nutted barrel?

 

[hoz53]

Just for the fun of it, I'm replacing a milsurp barrel with a new one as a nutted "prefit".
Barrel is a straight contour- tenon thread is .977-16 tpi.
I had started to make a nut for it, then had a lightbulb moment (maybe)- that's awfully close to the 1"-16 tpi of Sakos and Rugers.

Class 2, 1"-16 major is .989-.998, which means I'm between .009 and .018 smaller than the Tikka/Ruger.
.009 sounds a whole lot better than .018, but I have no idea where in that range Tikka and Ruger (and the aftermarket prefits) actually cut their barrels.

Would the Tikka/Ruger nut be too sloppy a thread fit on a .977 tenon to function correctly (even with Rocksett)?

you say thats a milsurp barrel so what is the firearm it is on/ you are working with?

 

[Ggmac]

sounds like a small ring mauser , BUT a barrel nut ? guessing ..... mauser sr is .980

 

[tobnpr]

If you have the action in hand and are able to make a nut why would you build a nutted barrel?

Fair question.
It's a bit of an experiment- if I can make this work acceptably, I may offer them for sale.
Being able to use a nut that's already commercially available has obvious advantages.

And... it's not a Mauser (they're not 16 tpi anyway).

 

[DaveTooley]

Just for the fun of it, I'm replacing a milsurp barrel with a new one as a nutted "prefit".
Barrel is a straight contour- tenon thread is .977-16 tpi.
I had started to make a nut for it, then had a lightbulb moment (maybe)- that's awfully close to the 1"-16 tpi of Sakos and Rugers.

Class 2, 1"-16 major is .989-.998, which means I'm between .009 and .018 smaller than the Tikka/Ruger.
.009 sounds a whole lot better than .018, but I have no idea where in that range Tikka and Ruger (and the aftermarket prefits) actually cut their barrels.

Would the Tikka/Ruger nut be too sloppy a thread fit on a .977 tenon to function correctly (even with Rocksett)?

Measure the pitch diameter. That's all that really matters.

 

[tobnpr]

PD is .929, so it's .024 under the small end 1-16 spec.
I'm thinking probably not close enough?

 

[Ggmac]

Fair question.
It's a bit of an experiment- if I can make this work acceptably, I may offer them for sale.
Being able to use a nut that's already commercially available has obvious advantages.

And... it's not a Mauser (they're not 16 tpi anyway).

Duh , you are correct.

 

[Dusty Stevens]

Thats going to be an awful small barrel

 

[tobnpr]

Thats going to be an awful small barrel

No different than Tikka or Ruger American...

 

[jackieschmidt]

The important measurement is the pitch diameter difference. That is what actually fits.

But common sense says it is going to be pretty sloppy.

Since the nut is acting as jam nut, rather than the actual centering of the barrel in the action, it might work fine for you.

But it will not be very aesthetically appealing to a customer. All he will see is a sloppy nut.

 

[Dusty Stevens]

The important measurement is the pitch diameter difference. That is what actually fits.

But common sense says it is going to be pretty sloppy.

Since the nut is acting as jam nut, rather than the actual centering of the barrel in the action, it might work fine for you.

But it will not be very aesthetically appealing to a customer. All he will see is a sloppy nut.

And a rimfire style sub 1” barrel

 

[Will Henry]

You can make the nut any size you like. In other words, you can thread the tenon-proper to the correct size for the receiver, then thread the barrel forward of that for the nut.
I had one action which had a thread of 1.125 and had a barrel with a shank diameter of 1.135". Plainly, there was not enough material to provide an adequate shoulder so I made a nut. The receiver thread was 14 tpi and I didn't want to cut that deep so I made the nut 1 1/8x24tpi and threaded the barrel ahead of the tenon for that. Screwed the barrel in until the headspace was right, then locked it in place with the nut. WH

 

[tobnpr]

You can make the nut any size you like. In other words, you can thread the tenon-proper to the correct size for the receiver, then thread the barrel forward of that for the nut.

Interesting point, hadn't thought of that.
I'm also considering opening the receiver threads up to 1"-16 to match the Tikka/Ruger spec.

And a rimfire style sub 1” barrel

Wow, Dusty- how do ya really feel?
Tikka and Ruger sell a hell of a lot of rifles, so apparently not everyone is aghast over a 1" barrel

 

[Dusty Stevens]

Interesting point, hadn't thought of that.
I'm also considering opening the receiver threads up to 1"-16 to match the Tikka/Ruger spec.

Wow, Dusty- how do ya really feel?
Tikka and Ruger sell a hell of a lot of rifles, so apparently not everyone is aghast over a 1" barrel

The tikka has a shoulder

 

[tobnpr]

^^^
Not the nutted prefits. Hey, you don't like it, that's fine. Everyone's entitled to their opinion.

 

[Hohn]

PD is .929, so it's .024 under the small end 1-16 spec.
I'm thinking probably not close enough?

Definitely not.