Devcon on barrel tenon?

Mram10us

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I recently rebarrelled a rifle and decided to put some devcon on the barrel threads before assembly to see if it would help dampen harmonics. Anyone try this before? Haven’t shot it yet to see results.
 
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tobnpr

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Well, first time I've heard of that one :eek:

Not going to do anything related to barrel harmonics. Barrel resonation stops at the barrel/shoulder junction.
I don't see any difference between what you did with epoxy, that's any different had you used red Loctite.

'Course, most of us use anti-seize, and not threadlocker on barrels.
 

P7M13

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Interesting. Not a path I would have chosen. Let us know if you observe any effects. Rule of thumb is that most humans can only detect changes greater than 10% of scale.
Without any hard data from calibrated LVDTs or Mems accelerometers, any claims as far as dampening will only be that.
 

Mram10us

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I know how it shot before, so if it shoots better, I’ll be happy :) made sure none got on either side of the recoil lug. Just the threads. I thought harmonics included the entire rifle, thus the importance of stress free bedding. Thoughts?
 

Clay Target Guy

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I know Loc-tite makes a "thread sealer" that is supposed to fill in gaps between threads but I don't remember the number. I think it is more of a pipe dope type compound but not sure.
Anyway I have never heard of doing this and don't think it would be something I would want to do myself. The threads I cut are usually cut tight enough that I use anti seize on them.
I would think that a good class 3 thread along with a square shoulder and square face/lug would do all that needs to be done. If the action is bedded, the barrel to action is a good fit, I would think the vibration is going to take the path of least resistance which should be toward the muzzle of the barrel (assuming the barrel is free floated). That is the way I see it but I may be wrong, but hey that is one of the reasons I am on here is to learn.
Let us know what you find out
 

Mram10us

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I know Loc-tite makes a "thread sealer" that is supposed to fill in gaps between threads but I don't remember the number. I think it is more of a pipe dope type compound but not sure.
Anyway I have never heard of doing this and don't think it would be something I would want to do myself. The threads I cut are usually cut tight enough that I use anti seize on them.
I would think that a good class 3 thread along with a square shoulder and square face/lug would do all that needs to be done. If the action is bedded, the barrel to action is a good fit, I would think the vibration is going to take the path of least resistance which should be toward the muzzle of the barrel (assuming the barrel is free floated). That is the way I see it but I may be wrong, but hey that is one of the reasons I am on here is to learn.
Let us know what you find out
I definitely don’t use sloppy threads. These are tight. Just curious if filling in as many gaps as possible with something that cures to 8k+psi will add anything
 

tobnpr

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I thought harmonics included the entire rifle, thus the importance of stress free bedding. Thoughts?

"Harmonics" generally refer to the barrel itself. Barrel resonation, the shock wave that travels from one end of the barrel to the other at supersonic speeds. If you're familiar with OCW (optimal charge weight) load development process, this seeks a "node" where the muzzle is at an optimal location when the bullet exits the bore as the barrel whips due to this shock wave.

(Stress free) bedding is a different issue, but a critical component in building an accurate- as in REPEATABLE, rifle.
If the action moves in the stock under recoil, and does not return to EXACTLY the same position, this will affect accuracy. It's not related to barrel harmonics, but just like the barrel itself (most important, IMO) a critical factor in what makes for an accurate rifle.

Consistent accuracy, is nothing more than consistent repeatability- getting the rifle system, to do exactly the same thing, every time.

Thread fit of barrel to receiver is far from critical, and I'll take a slightly loose thread fit over one that's too tight every day. Especially in the realm of production actions, the threads will not be precisely perpendicular to the receiver ring- this is why we single-point these (true) the actions.

If the thread fitment is too tight, there will not be enough "play" in the crests/roots to allow the barrel shoulder to mate up precisely to the receiver ring (these two surfaces MUST be true/perpendicular to the bore and raceway).
Threads bring the parts together. The shoulders/mating surfaces align them.
 

Mram10us

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"Harmonics" generally refer to the barrel itself. Barrel resonation, the shock wave that travels from one end of the barrel to the other at supersonic speeds. If you're familiar with OCW (optimal charge weight) load development process, this seeks a "node" where the muzzle is at an optimal location when the bullet exits the bore as the barrel whips due to this shock wave.

(Stress free) bedding is a different issue, but a critical component in building an accurate- as in REPEATABLE, rifle.
If the action moves in the stock under recoil, and does not return to EXACTLY the same position, this will affect accuracy. It's not related to barrel harmonics, but just like the barrel itself (most important, IMO) a critical factor in what makes for an accurate rifle.

Consistent accuracy, is nothing more than consistent repeatability- getting the rifle system, to do exactly the same thing, every time.

Thread fit of barrel to receiver is far from critical, and I'll take a slightly loose thread fit over one that's too tight every day. Especially in the realm of production actions, the threads will not be precisely perpendicular to the receiver ring- this is why we single-point these (true) the actions.

If the thread fitment is too tight, there will not be enough "play" in the crests/roots to allow the barrel shoulder to mate up precisely to the receiver ring (these two surfaces MUST be true/perpendicular to the bore and raceway).
Threads bring the parts together. The shoulders/mating surfaces align them.
I would argue the harmonics refer to anything touching the barreled action. If you bolt it to a wood stock v bolting it to a large steel block. I'm sure Alex Wheeler can speak to this better than I can.

I can't imagine having threds so tight that you cannot get the shoulder of the tenon and action face to mate if machined correctly. Again, I allow play in the threads and this would simply act as a filler and maybe change harmonics. Not sure, just theory but we will see in the next couple days :)
 

J E Custom

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I recently rebarrelled a rifle and decided to put some devcon on the barrel threads before assembly to see if it would help dampen harmonics. Anyone try this before? Haven’t shot it yet to see results.


Your gunsmith will love you for that. :eek: Believe it or not, Not to long ago I had to remove a barrel that was a Remage (Remington/Savage cross) that he thought it would allow him to screw the barrel on hand tight and not move. To remove it, I had to use well over 150 ft/lbs and warm it with my hot air gun.

I can't say If it will change the harmonics, But it will be almost impossible to remove without ruining the barrel or the action. Sorry to be so blunt.

J E CUSTOM
 

Mram10us

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Your gunsmith will love you for that. :eek: Believe it or not, Not to long ago I had to remove a barrel that was a Remage (Remington/Savage cross) that he thought it would allow him to screw the barrel on hand tight and not move. To remove it, I had to use well over 150 ft/lbs and warm it with my hot air gun.

I can't say If it will change the harmonics, But it will be almost impossible to remove without ruining the barrel or the action. Sorry to be so blunt.

J E CUSTOM
I am my gunsmith :) Devcon is easy to remove with a bit of heat. I don't torque to even 100ftlbs, but that is a whole other debate. I'll post results. Was hoping some had tried this already being the innovative community we are
 

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