Tube tightening.

S

starik

Guest
I wonder if an aluminum tube which tightend to the muzzle can effect the inside diameter of the muzzle? If the answer is yes, then I would be able to conrol the choke of the muzzle with increasing the torque. Also , in 2013 action can the torque at the breech can effect the chamber diameter? How strong should be the tourque on the screws at the breech?
Guy.
 
Friend Starik

Friend Starik:

You've asked a very interesting couple of questions.....

Friend Doug, who posts on this forum, started a web site for me.....I have not decided whether or not to use it.........but in case I do I have been making a list of subjects to write about......things that I probably wouldn't put in Precision Shooting Magazine......

I am going to put your fine questions on my list.......I'm sure there are other folks on this forum that will be glad to give you some answers until that time.

http://billcalfee.org

Your friend, Bill Calfee
 
Quite a while ago this very thing was discussed at length, don't know if a search would bring it up.

It went something like this,

Bill posted that one should be careful and not overtighten the muzzle tuner as you could cause too much choke or constriction i.e.: reduce the inside diameter of the barrel.

A guy from L.A. who had been attending our matches for some time was a machinest (sp) and gunsmith who read Mr. Calfees post and tried it out himself and was not able to measure any difference. So he clamped it (the muzzle) into some part of his lathe and cranked it down tight, putting many times the force that you could get from the aluminum collar of the tuner and still could not measure any difference in the inside diameter.

This went back and forth and folks got angry and unkind things were said.

Bill was using another person to post for him, and I ended up as messenger boy for the guy with the lathe. This further complicated the discussion.

In the end, Bill said that the best way to confirm the fact was to slug the barrel without the tuner, and then mount the tuner and crank it down tight, then slug the barrel again and you could feel the bore get tight where the tuner collar was.

And that's where it ended, I think.
 
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I think Bill was correct, and it takes slugging it to find out the difference. If you have a barrel that is very uniform in dimension, from one end to the other and hardly no choke at all, or no choke, you can feel the difference when slugging it after torqueing a tuner up tight. I know this because I have a barrel like that I've been playing with, and I've done it. However if you have a barrel with 4-5 tenths of choke in it, it's hard for me to tell the difference when slugging it, because of the choke, even though the tuner is probably constricting it a bit.

As far as trying to control choke with a sleeve tightened at the muzzle, I'd doubt it because I'd guess the barrel might possibly put into an out of round state, then it might not? Depends on luck! It'd be a simple experiment to try it and see how it worked.
 
This question should have been put to any engineer, or for that matter any second year engineering student. Any sleeve, of any material, put on the barrel, at muzzle or breech, with interference fit, or with collar clamped with screws, WILL CAUSE THE BORE TO CONSTRICT. There is no question of this, the only question is how much. The sleeve, or collar, will exert a pressure between it and the outside diameter of the barrel. This pressure even if it were only 1 psi will cause the bore to move in to a smaller diameter. High interference fits or tightly clamped collars produce pressure of several hundred to several 1000 psi. This bring bores in from a few .0001" to several .001". Larger ratios of outside diameter to inside diameter will allow the bore to move in to a lesser degree.
 
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How tight should the screws clamping the tuner to the barrel be?
 
Gonefishing,
I have heard just tight enough so it's doesn't fall off and stay put.
Eddie
 
pacecil said:
This question should have been put to any engineer, or for that matter any second year engineering student. Any sleeve, of any material, put on the barrel, at muzzle or breech, with interference fit, or with collar clamped with screws, WILL CAUSE THE BORE TO CONSTRICT. There is no question of this, the only question is how much. The sleeve, or collar, will exert a pressure between it and the outside diameter of the barrel. This pressure even if it were only 1 psi will cause the bore to move in to a smaller diameter. High interference fits or tightly clamped collars produce pressure of several hundred to several 1000 psi. This bring bores in from a few .0001" to several .001". Larger ratios of outside diameter to inside diameter will allow the bore to move in to a lesser degree.
Click to expand...


The question was put to an engineer with a Masters degree from Stanford who works for Ferrari on their race team (his initials are on the conrods of their F1 car). He said that in theory there could be constriction or decreasing interior demensions but at that level the fact that steel is not stable and the molecules are actually moving around that measurement would probably not be possible.

So as Bill said and Kent seconded, it is something that has to be felt, and then only in certain situations. I think.
 
How about cutting slots inside the collar and putting rubber O-rings in them and then just tightening until the collar bottoms the orings?
 
This was discussed a long time ago, maybe 5 or 6 years ago. I had a barrel in 2000 that was pretty good. I could feel the constriction using a bullet as a slug. A longer slug may not feel in. I experimented an found for that particular barrel I could not feel 9 inch pounds but could feel anything higher. I have used 9 inch pounds on all my barrels since then and have not had a tuner fall off. Rich
 
Not being an second year student I have some questions>
If the constricting collar is Al and not a steel of same alloy and hardness as barrel and not the same ratio of barrel diameter to bore would not the softer and thinner clamping material stretch in a differing ratio to the compression of the barrel material?
And if screws are used to force compression of collar what stress and stretch is involved here? Also would not the modus of compression act in all dimensions of length as well dimensions of diameter?
And what about the lack of memory of ferrous metals-once compression occurs what amount of it will not return fter compression relaxed?
I am confused.
 
Experts

I asked this same question of Doug Shilen back in 2000. His answer, was you can't change the inside diamentions of a 22RF, using the present style tuners. His reasoning, was you would strip the Aluminum clamp before you reached sufficent torque to cause any changes. That was good enpugh for me.
 
The rubber O-ring deal won't work because the tuner needs to be firmly attached to the end of the barrel to cancel the barrel vibrations.

I have a very long tuner on a prone rifle (11" long), and I didn't want to clamp and epoxy it on the barrel before I found the "right position" for the front sight, so I just silicone glued it on. I never could get it to "tune" until I finally clamped and epoxied it, and then it really made a difference.

Hose
 
I am NOT an engineer. But I do not understand how the soft aluminium collar can constrict the steel of a barrel. Logic tells me that the aluminium collar would stretch rather than have the barrel constrict.
College
 
Yep, it's a real poser. Gonna give ya wrinkles on your forehead if you pose on it too long.
1088.gif
 
Try it

Hey Guy (s) :)

I have tried this with variuos results on the torque from barrel to barrel. The groups gets better and when overdoing they open up again. In my experience the best results with my barrels are between 4 to 6 Nm torque. I have two screws on the clamp and they are torqued differently as a rule. Also by clamping flush or maybe a little to the rear of muzzle the group pattern changes. You just have to try it.
 
tubes

i read this and wondered aren't you supposed to have some
choke in the muzzle end of your barrel can you build it in by
tightening something down on it if so is it controllable and
is it permanent? if you take the tube off does the barrel open
back up? if you had a barrel that needed some choke could
you build it in from the outside?
 
i wondering

if i might have put my tuner on too tight.
if so can i redo it, or ?
 
Snug

Tom:
You can loosen and retorque to no more that 20 inch pounds. If you had it fitted properly, that's more than enough. You don't want to damage the treads of the tuner.
 
Øyvind said:
Hey Guy (s) :)

I have tried this with variuos results on the torque from barrel to barrel. The groups gets better and when overdoing they open up again. In my experience the best results with my barrels are between 4 to 6 Nm torque. I have two screws on the clamp and they are torqued differently as a rule. Also by clamping flush or maybe a little to the rear of muzzle the group pattern changes. You just have to try it.
Click to expand...

Hi Øyvind ... Got a question ... does Nm mean Newton Meters? If so, does 4 to 6 Nm equate to like 35 to 53 inch pounds?

Fred
 
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