Change of barrels - tension

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Change of barrels - torque

I change barrels myself with my current action, but got to think - how "hard" should I really twist the barrel into the action? Does it really mather if it is just "hard" or "as hard as can get it"? It is an blueprinted rem-action.
 
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Precision Shooting mag had a decent article about barrel tension a month or so ago. If I recall.

It shouldn't really matter as long as the threads and the face of the action are true, along with the threads of the barrel and its shoulder.
 
All I can tell you is that excessive torque can damage a receiver, sometimes badly.
I have an Enfield action whose receiver ring was damaged due to excessive torque, and I'll have to custom fit a replacement barrel, and can't use the standard barrel made for this action.
Those who've rebarreled a lot of M1917 actions and P-14 actions found that at some point in production excessive torque had been common, probably early WW1 production and the original barrel hand to be cut out of the receiver ring to avoid doing more damage, and even then its common to find cracks in those reciver rings.

I've been told by a smith who rebarreled many rifles of various types that 60-70 foot pounds of torque is about right for any action type.

Some makers of takedown rifles say hand tight is actually enough, though these are generally not high intensity chamberings.
 
I have read the link now - many thanks. I kind of understand that hand tightened barrels is not the way to go with center fired rifles ment for BR. Am I correct?
 
I have read the link now - many thanks. I kind of understand that hand tightened barrels is not the way to go with center fired rifles ment for BR. Am I correct?

No I don't think you'd want a take down barrel on any modern target rifle, though it may have been done in the Black powder days.
A barrel that screws in hand tight and is then snugged up using a torque collar and wrench would be more rigid of course. Even then I've seen this sort with the scope mounted to an extended mounting afixed to the barrel and reaching back over the action, not something you'd want for benchrest shooting I'd think. Just mentioned the takedown barrels for reference on strength needed to safely handle medium high pressures with least amount of torque.
 
Is there any consensus about how a barrel that is "too loose" will perform? Will there be verticals, horisontal shots - or just all over the place?
 
Is there any consensus about how a barrel that is "too loose" will perform? Will there be verticals, horisontal shots - or just all over the place?
Take all the screws loose on your scope....same result. Why would you want a loose barrel in the first place?
 
All I can tell you is that excessive torque can damage a receiver, sometimes badly.
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I know I have never seen enough torque put on a benchrest quality machined barrel screwed into a benchrest quality action to cause any damage and I seriously doubt if you have either.
 
Even then I've seen this sort with the scope mounted to an extended mounting afixed to the barrel and reaching back over the action, not something you'd want for benchrest shooting I'd think.
Actually, I do this on a number of my benchrest rifles. I use a barrel block, with the scope on the block, cantilevered back over the action. There is a certain amount of extra work to use a barrel block, and additional weight. I've used this setup on short range HV rifles (13.5 pounds), and 1,000 yard Light Guns (17 pounds). It could be done with LV (10.5 pounds), but the engineering would require some pretty good planning.

BTW, use of a barrel block often makes changing barrels harder. Clocking the barrel is not as easy as you might think for rifles having a conventional stock -- i.e., not a rail gun. How hard it is depends on several factors. The easiest kind of block for clocking simplicity is a clamping V-block.

Is there any consensus about how a barrel that is "too loose" will perform? Will there be verticals, horisontal shots - or just all over the place?
Think it through. Who would have done the exhaustive testing needed to come up with the answer? All you're apt to get is urban legends -- what I call the "what some guy said channel." But in passing, Tony Boyer did an interview published in The 1999 Precision Sooting Annual (think that was the year), where he remarked that he had a rail gun with a loose barrel. It was an inconsistent performer. He found the loose barrel just about the time the rifle had lost its high-competitive use -- about 500 rounds. This should tell you that a loose barrel won't always make its condition known in an obvious manner, or a Tony Boyer would have determined it quite quickly.

* * *

To me, this thread illustrated a common problem with coming onto the Centerfire Benchrest forum with certain kinds of questions. I don't doubt that Old Gunner has seen cracked P-17 actions. And oddly enough, they *have* been used for benchrest actions in 1,000 yard competition, as they would take the Rigby-sized cases. But they're not typical; they are an exception to the general BR action. BTW, the one's I've seen all used barrel blocks . . .

And who has done the testing needed to determine if the method of hardening that steel, with the various loads on the threads and shoulder from both tightening and firing, would cause the cracks *only* from tightening, or if there were multiple factors?

In order to give any sort of reasonable answer in the short space of an internet forum, you have to make a lot of assumptions. You have to generalize. This all works better when the questioner and responders can minimize differences, and one of the best ways to achieve is to rule out non-benchrest setups.
 
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Take all the screws loose on your scope....same result. Why would you want a loose barrel in the first place?

I think you misunderstood me - I do not want a loose barrel. However, I have struggled a bit with my current gun before I finally understood that my barrel torque might not have been as hard as it should have been, or perhaps even far from it. Knowing my problems I could perhaps get a step closer to why my current gun has not performed as I hoped it should have.





Think it through. Who would have done the exhaustive testing needed to come up with the answer? All you're apt to get is urban legends -- what I call the "what some guy said channel." But in passing, Tony Boyer did an interview published in The 1999 Precision Sooting Annual (think that was the year), where he remarked that he had a rail gun with a loose barrel. It was an inconsistent performer. He found the loose barrel just about the time the rifle had lost its high-competitive use -- about 500 rounds. This should tell you that a loose barrel won't always make its condition known in an obvious manner, or a Tony Boyer would have determined it quite quickly.

I get it - but I must add that this is kind of the answer I was looking for also. After all I consider myself I newbee within the BR-shooting knowing that I have years to come where I will learn more an more. But finding my barrel being what I would consider being too loose - almost no power needed to put on the action wrench to loosen the barrel - I know the problems I have had with my gun upto now. Hence this could help me identify if this was the main problem or if there are other potential problems not yet found... But your answer was also very helpful to me, absolutely.
 
I know I have never seen enough torque put on a benchrest quality machined barrel screwed into a benchrest quality action to cause any damage and I seriously doubt if you have either.

Is that an attempt at creating a strawman?

You aren't likely to see damaged receivers on recent manufacture rifles is because the vast majority of gunmakers learned long ago that overtorquing damages the receiver.

The Enfield receiver I have (a No.1 , which I didn't mention) was most certainly damaged by excessive torque. The metal of the receiver ring was deeply indented and bulged into the undercut of the barrel reinforce.
I've shaved the face of the ring to remove the unevenly indented portion and I have set back the shank of a No.4 barrel by aproximately half a thread so that it will clock in with the etractor cut out lined up properly. I'll then have to deepen the chamber with a finish reamer.
Not sure if I'll complete this project of not, I may bore the barrel out to .410 rather than trust that receiver with a full power rifle chambering.
The M1917 receivers with cracks from over torque are well known. Recent purchases from the CMP have brought this to light.
Due to the high Nickel content of the steel used the rifles didn't fail in service, but the cracked receivers make them unsuitable for restoration or custom rifle building.
These barrel often require relief cutting to remove the over torqued barrel without causing cracks to receivers not already damaged.
How many rifles were effected is anybody's guess.

Use your own judgement on your own rifle. If you crack a receiver it should come out of your pocket.
 
I think you misunderstood me - I do not want a loose barrel. However, I have struggled a bit with my current gun before I finally understood that my barrel torque might not have been as hard as it should have been, or perhaps even far from it. Knowing my problems I could perhaps get a step closer to why my current gun has not performed as I hoped it should have.



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Tightening a barrel on a benchrest rifle ain't really rocket science. Loose won't work for sure. How tight? Tight enough that it will not move. How much is that. I'll wager somewhere over 75 ft/lb and somewhere less than 900 ft/lb..

Old Gunner. I don't do strawmen!! And I don't do Enfields. I've sporterized a few 1917's but that ain't benchrest.

Think about it guys, like I said, it ain't rocket science!! A PPC case will hold about 30 grains or so of powder. Would you put 30 grains of Bullseye or 30 grains of 5010 and expect it to work????
 
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