Threading for tuners?

[wk4036]

I use slip on tuners on Rimfire rifles but would like to know if cutting/threading for a screw on causes the muzzle of the barrel to open up on centerfire rifles?

 

[Dusty Stevens]

Yes

 

[gunsandgunsmithing]

Yes

Prove it Dusty... There are numerous tuners that only require about .025" be removed before threading of common .900 rf BR bbls. I have proven to myself two things, that if I machine a button rifled barrel down from 1.000(nominal) to 5/8-24 threads, I can measure about .0002" growth in the bore. I have NOT detected that growth in cut rifled barrels OR barrels machined from 1.000 to say 3/4".
Most tuners(not all) are 7/8-32 tpi. I have never detected bore change at that thread size, even when starting with a 1.450 barrel..not cut nor buttoned.

The other thing is rf vs cf. I can not tell that a tenth or two matters on cf, where muzzle pressures can be 5,000-8,000psi vs a rf bbl being in the hundreds of psi. Keep in mind, the barrel grew more than that at it's peak of 60,000-70,000psi and the soft copper clad lead bullet simply obturated to the bore it's being forced down...and as pressure drops, you have a "natural" choke on a cf that rf does not have.

If I can't measure it and I can't see it on paper, I doubt the rest of us can, either.

I will say that due to the far lower muzzle pressures, "choke" in the bore is more critical to rf. I think with cf, you'd be hard pressed to prove a tenth or two of growth is even detectable on target.

So, even if it grows, does it matter? And you have to first prove growth to me on both cut and buttoned barrels. For our purposes here, we don't have to get into hammer forged, which may well get tighter after cutting the od.

I've sold thousands of tuners and installed probably a few hundred on cf bbls. Many of which, both cut and buttoned are currently winning National level matches and hold numerous world records. The rf tuners are most commonly clamped on, because of this belief, Keep in mind that Calfee preaches that machining for a large tenon on the chamber end creates a constriction at the shoulder. Seems like an easy enough fix to me...make the action so that this "constriction" gets cut out by the reamer. Oh, but it doesn't happen if we just stay with .850-.900 contours machined to .750-16 and at the point where pressure is highest...Lots of bs in that stuff, if you bother reading it.

More later. I like this subject!

Again, just my 2 cents worth.

 

[Dusty Stevens]

Prove it Dusty... There are numerous tuners that only require about .025" be removed before threading of common .900 rf BR bbls. I have proven to myself two things, that if I machine a button rifled barrel down from 1.000(nominal) to 5/8-24 threads, I can measure about .0002" growth in the bore. I have NOT detected that growth in cut rifled barrels OR barrels machined from 1.000 to say 3/4".
Most tuners(not all) are 7/8-32 tpi. I have never detected bore change at that thread size, even when starting with a 1.450 barrel..not cut nor buttoned.

The other thing is rf vs cf. I can not tell that a tenth or two matters on cf, where muzzle pressures can be 5,000-8,000psi vs a rf bbl being in the hundreds of psi. Keep in mind, the barrel grew more than that at it's peak of 60,000-70,000psi and the soft copper clad lead bullet simply obturated to the bore it's being forced down...and as pressure drops, you have a "natural" choke on a cf that rf does not have.

If I can't measure it and I can't see it on paper, I doubt the rest of us can, either.

I will say that due to the far lower muzzle pressures, "choke" in the bore is more critical to rf. I think with cf, you'd be hard pressed to prove a tenth or two of growth is even detectable on target.

So, even if it grows, does it matter? And you have to first prove growth to me on both cut and buttoned barrels. For our purposes here, we don't have to get into hammer forged, which may well get tighter after cutting the od.

I've sold thousands of tuners and installed probably a few hundred on cf bbls. Many of which, both cut and buttoned are currently winning National level matches and hold numerous world records. The rf tuners are most commonly clamped on, because of this belief, Keep in mind that Calfee preaches that machining for a large tenon on the chamber end creates a constriction at the shoulder. Seems like an easy enough fix to me...make the action so that this "constriction" gets cut out by the reamer. Oh, but it doesn't happen if we just stay with .850-.900 contours machined to .750-16 and at the point where pressure is highest...Lots of bs in that stuff, if you bother reading it.

More later. I like this subject!

Again, just my 2 cents worth.

Slugging will show a lot when you learn how to do it right. I never said it mattered i just said it did. I need to fix my air gage wand, it was a lot quicker. Im not going to quit using a tuner over it. A clamp on tuner can change the bore way more than turning it down if you dont do it right.

 

[wk4036]

Ok what if we glued/loctited it on?
I am just starting my venture into the LV game and have oh so many questions.

 

[gunsandgunsmithing]

Ok what if we glued/loctited it on?
I am just starting my venture into the LV game and have oh so many questions.

Just give me a call next week and we can go over all of it. Happy to be of help.

 

[Dusty Stevens]

Ok what if we glued/loctited it on?
I am just starting my venture into the LV game and have oh so many questions.

A centerfire tuner needs to be threaded on the barrel and that needs to be done properly. Call mike above and he can fix you up