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Has any made some tool or device to measure barrel tension?
I was thinking about some form of jig that goes over the barrel say behind the flash hider that attaches a beam style torque wrench, then you could slip a piece of paper under the front band at the lip, apply pressure to the torque wrench and when the paper falls out mark the reading.
Tell me what you think.

Casey
 

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I don't think that much precision measuring is necessary - and how is the range of 'acceptable readings' determined?

I think a simple 'handsqueeze' test is adequate. If the necessary pressure is similar to squeezing soft foam packing, then that's too little.
If the needed pressure is similar to squeezing a tennis ball, that's fine.

The purpose of the draw tension (pressure) is to cause the barrel band to consistently reposition itself with the ferrule for each shot. If the tension is adequate to perform that, then it's good.

The amount of tension (pressure) itself is not important - only that the band and ferrule are consistently positioned.

Jay Kosta
Endwell NY USA
home of 2016 Little League WORLD Series Champions
 

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In addition to re-positioning, I thought it was also to reduced barrel whip. If that is the case, then there might be different "best" values for each type (SOCOM/Scout/Standard) as well as barrel thickness (med./heavy)?



(maybe I should just shut up and go back under my rock)
 

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The purpose of the draw tension (pressure) is to cause the barrel band to consistently reposition itself with the ferrule for each shot. If the tension is adequate to perform that, then it's good.

The amount of tension (pressure) itself is not important - only that the band and ferrule are consistently positioned.
Yes Dougboffl you are exactly correct.

The statement above is only half right.
The part about repeatability is correct. The part about the amount of tension is not.

Varying the tension changes the barrel vibration harmonics - the object of which is to move the null point coincident with the end of the barrel. It is not only important it is of the most importance where accuracy is concerned. This is why we see adjustable harmonic tuners proliferate in all the competitive disciplines where they are allowed.

EARTHQUAKE

I think you have a neat idea and you should follow up on it. However, it is my believe that it won't really help in the long run. My reasoning is that, since every rifle is an individual, there is no magic number a person could torque to. Because of different barrel weights, lengths, materials, etc. there is no one value that will work.
It ain't like a known torque setting for barrel to receiver installation for example. Does that make any sense?
 

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I think you could take 5 identical barrels and the harmonics will be different which is probably one of the reasons every rifle shoots a little different.
Interesting concept if you could do it with repeatable results.

Has any made some tool or device to measure barrel tension?
I was thinking about some form of jig that goes over the barrel say behind the flash hider that attaches a beam style torque wrench, then you could slip a piece of paper under the front band at the lip, apply pressure to the torque wrench and when the paper falls out mark the reading.
Tell me what you think.

Casey
 

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...
Varying the tension changes the barrel vibration harmonics - the object of which is to move the null point coincident with the end of the barrel. It is not only important it is of the most importance where accuracy is concerned. This is why we see adjustable harmonic tuners proliferate in all the competitive disciplines where they are allowed.
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Do you have any information about what actions should be done to change the tension to achieve the null point movement of the barrel? Other than 'rebed and try again'.
Maybe if the tension is very low to start, then testing with a series of shims might show some change.

I know that with some bolt-action rifles, people have good results with adjusting the torque of the receiver bedding screws.
But I'm not familiar with a process for draw tension on M1 /M1a.

Jay Kosta
Endwell NY USA
 

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The only method I'm really familiar with is to bed the rifle with a bit of tension. Then add progressively thicker shims (I used milk jugs because of their lubricity) as you spend time on the range. There was always a point, with me, where it became apparent what thickness the gun liked.

Here is one example. My photography is poor but hopefully it will give you an idea. This shim is from the side of a milk jug. It has moved slightly with use but seems to work the same.
 

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The only method I'm really familiar with is to bed the rifle with a bit of tension. Then add progressively thicker shims (I used milk jugs because of their lubricity) as you spend time on the range. There was always a point, with me, where it became apparent what thickness the gun liked.
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Thanks for the info. I agree that your method is good for determining when more tension would be beneficial.

Jay Kosta
Endwell NY USA
 

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Here's an easy way to check.

Support the rifle upright on your workbench with the foreend of the stock supported on a block right behind the front ferrule,at the edge of the bench, with the barrel hanging over the edge. Hang a shopping bag on the barrel right in front of the band. Start filling the bag with beers until your thinnest feeler gauge will just slip between the tab on the band and the bottom of the ferrule.

Count the beers. A beer in an aluminum can weighs 13 ounces. A soft drink is probably very close to the same weight.
 

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'Merica!

Here's an easy way to check.

Support the rifle upright on your workbench with the foreend of the stock supported on a block right behind the front ferrule,at the edge of the bench, with the barrel hanging over the edge. Hang a shopping bag on the barrel right in front of the band. Start filling the bag with beers until your thinnest feeler gauge will just slip between the tab on the band and the bottom of the ferrule.

Count the beers. A beer in an aluminum can weighs 13 ounces. A soft drink is probably very close to the same weight.

And this my friends is why America is the greatest country on Earth!
A simple, ingenious solution..... and once you get your answer, you get rewarded with refreshments.
If this were, say Germany for instance, someone would have invented a device resembling a nuclear particle accelerator that costs a million bucks and needed a master's degree to run. Sorta like my wife's BMW.
 

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The only method I'm really familiar with is to bed the rifle with a bit of tension. Then add progressively thicker shims (I used milk jugs because of their lubricity) as you spend time on the range. There was always a point, with me, where it became apparent what thickness the gun liked.

Here is one example. My photography is poor but hopefully it will give you an idea. This shim is from the side of a milk jug. It has moved slightly with use but seems to work the same.
Funny you used milk jug plastic for its lubricity, DaveP used a small ball bearing with a divot in the ferule too do the same thing.
 

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DaveP used a small ball bearing with a divot in the ferule too do the same thing.
How industrious!
I am not only far to lazy for that, I am certain I haven't the engineering prowess to pull it off. My hat is off to DaveP.
 

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AHHHhhhhhh ...
one of my favorite topics ...
barrel tensioning on the M14 rifle system ...
aka ..
chasing after "harmonic convergence" ...
aka ...
TACTICAL VOODOO!

I gave up on worrying about all that magical/mystical barrel to forend tensioning stuff,
and simply eliminated the forend to ferrule barrel connection point.

By relocating where and how the barrel connects to the forend [ not to be confused with making it so the barrel does NOT connect to the forend ... aka "Free Floating"], we significantly simplified the M14 mystical/magical/voodoo effect.

By using a much modified, reinforced op rod guide, bedded SECURELY into matching buttresses in the aluminum fore end, we shifted the point of connection back several inches.

By making the op rod guide tension SCREW ADJUSTABLE, we made a torque wrench do the same thing as the previously required MAGIC WAND/VOODOO rituals. AND YOU CAN CHANGE THE TENSION AT THE RANGE CONVENIENTLY AND QUICKLY TO TUNE TO THE SPECIFIC LOADS!!

The results speak for themselves.
Just look at the list of top ten M14 rifles at last years "Challenge".
Two of the top ten used Blackfeather alloy chassis systems.
Science over magic??
maybe not totally,
but the initial results are promising,
and encourage more experimentation in this direction.
 

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By barrel tension, do you mean what forum members frequently call "fore end draw," the force of contact between barrel band and the stock ferrule? Measuring it is easy. Building a rifle with a particular draw value is not quite so easy and requires several steps in the bedding process. Determining the optimum draw for a particular combination of stock and barrel is more difficult, although extensive research will lead you to a range of "draw" used by several prominent rifle builders. Some advocate the coat hanger method and take whatever draw results.

I clamp the rifle in a vise, gripping the barrel between the flash suppressor and gas plug. I use a luggage scale hooked to a strap that goes around the fore end about an inch from the ferrule. I place a narrow strip of paper between the band and ferrule. I pull the scale until the paper falls free.

Sorry, for me, your torque idea does not compute.
 

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I clamp the rifle in a vise, gripping the barrel between the flash suppressor and gas plug. I use a luggage scale hooked to a strap that goes around the fore end about an inch from the ferrule. I place a narrow strip of paper between the band and ferrule. I pull the scale until the paper falls free.
That's an excellent method. I have a Lyman digital trigger pull gage that would work the same way. The max reading on the Lyman is something like 25 pounds, so it should even work for a heavy barrel in a McMillan... but I don't have one of those.
 

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barrel tensioning on the M14 rifle system ...
aka ..
chasing after "harmonic convergence" ...
aka ...
TACTICAL VOODOO!

I gave up on worrying about all that magical/mystical barrel to forend tensioning stuff,
and simply eliminated the forend to ferrule barrel connection point.
Nope, not voodoo - science.
The Rimfire Benchrest guys did most of the original work because they could not fiddle with ammunition. The centerfire benchrest guys soon took notice and really ramped up the effort. Theose guys use a hybrid system now. They free float the barrel and adjust the length to where the muzzle is at a null point. The rimfire guys use a tuner on the muzzle.

FWIW, the Marines still use the "free float" idea (last time I looked anyway)
The free floating of barrels was the be-all, end-all in the '60's. My dad made bunches of Model 70's that way.
The problem is that if you can't "touch" the barrel then you don't have any means of tweaking the rifle if it doesn't "shoot".
Adjusting the pressure allows that tuning.
 
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Funny you used milk jug plastic for its lubricity, DaveP used a small ball bearing with a divot in the ferule too do the same thing.
I considered drilling a small hole in the stock ferrule and installing a bearing. All I have done to date is polish worn surfaces on the stock ferrule and barrel band, then apply a dab of good grease.
 

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Nope, not voodoo - science.
The Rimfire Benchrest guys did most of the original work because they could not fiddle with ammunition. The centerfire benchrest guys soon took notice and really ramped up the effort. Theose guys use a hybrid system now. They free float the barrel and adjust the length to where the muzzle is at a null point. The rimfire guys use a tuner on the muzzle.

FWIW, the Marines still use the "free float" idea (last time I looked anyway)
The free floating of barrels was the be-all, end-all in the '60's. My dad made bunches of Model 70's that way.
The problem is that if you can't "touch" the barrel then you don't have any means of tweaking the rifle if it doesn't "shoot".
Adjusting the pressure allows that tuning.

Ok, I'll bite. How does one free float a barrel on the m14 platform?
 
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