Loose barrel

[RC20]

While clearly the compound used at factory is not Anti Seize, there certainly is something on the threads.

I would not expect the factory to use a thread substance to enable them to be worked on, it seems to be more a lock tite type agent.

NSS is the one that recommends the anti seize. I like it because it lubes the threads, ego it goes on and screws out easier.

So far no loosening issues with that and the 50 ft lobs of torque.

Which leads me to believe if there is a problem its the nut thread interface that is giving. While it could be the nut, it might be a combination of nut that is at max allowance and the barrel threads at minimum.

There is a reason its getting loose. Its not lube, torque allowance is very wide (or works) There is no magic though the cause can be a bugger to pin down.

[RC20]

also call them and ask what they recommend their barrels torqued WITH compound. The answer will be 70#s unless I just got a bogus representative.

If you have worked on equipment, when an mfg specs a lube (or any other substance) they are very specific as to what that lube is.

It may be anti size, it may be engine oil, it may (in the old days) been some stuff called peanut butter. But it will be specific.

The reason is each material on the threads has an affect on torque. So, you don't just want to know what the torque is with a generic compound, you need to know what is used with that torques spec.

When I was younger (much) my brother had a truck that the staring box kept loosening the bolts up on.

We could find nothing wrong.

It was not until some years latter I found that the suspect was that someone had put those bolts into the plastic range and were stretching.

In that case it was very subtle as there is a clear sign of plastic stretch on a bolt, but in this case it had to be barely there and they looked normal.

[J.Baker]

That is interesting because the last 3 rifles I built ALL came with some sort of compound on the threads. 2 were brand new rifles and the other 2 still had their factory barrels so never been switched. What is this mysterious compound then?!?

It's exactly what I said it was in my first response - residue from the tumbling processes. The barreled actions are wet tumbled in a rotisserie-style vibratory tumbler that holds 42 barreled actions. The slurry of water and tiny grit that comes off the tumbling media created in this process works it's way under the barrel nut and into the threads. Those tiny little spheres you find lodged in the threads are grit from the media. When it dries it's very hard which is why some think it's some kind of thread locker.

The blue and orange machine is the rotisserie vibratory tumbler. The orange drum is mounted on springs.
3119

This is the rotisserie cartridge that holds 42 barreled actions and rotates within the orange drum as it vibrates.
3120

Here the cartridge is in the vibratory tumbler with the course media which provides a matte finish. A fine media (green cones) is used after this step for the Classic models with the high polish finish.
3121

Close-up of the cartridge in the tumbler.
3122

This is what the parts look like after tumbling. Note the slurry residue that's all over the inside surfaces, that's what is working it's way under the nut that you think is anti-seize.
3123

The barreled actions are then dipped in a series of degreaser/cleaner vats, but since there is no agitation it can't flush the residue out from under the nut.
3124


also call them and ask what they recommend their barrels torqued WITH compound. The answer will be 70#s unless I just got a bogus representative.

Customer Service rep's are merely phone jockeys with little to no hands on experience or expanded knowledge on the products. Such rep's are given a list of FAQ's that customers often have with standardized answers that they give when someone asks them. Such is common practice for any customer service center.

[RC20]

Well egg on my face and highly embarrassed. I used to be a pretty good reader.

I glossed over and or missed the part about the residue plain and simple.

I apologize for doing so, that should not happen.

It may not make it better but I can at least make it clear outstanding information was presented and not read.

[huntin1]

Dang, just bought a tube of anti seize and am going to replace the barrel on my 10FP, guess I don't need it. So just leave the threads dry?

[RustyShackle]

Depending on the anti seize and the bbl material maybe shouldn't mix anyway... I used anti seize on mine and so far all is well with no issuess. I doubt as course as threads are that you should have a problem. If chrome moly I wouldn't worry, stainless is another story.

[huntin1]

The barrel is 416 stainless, the anti seize is Loctite sold by brownells. It cost me $7, no big deal if I don't use it. Every thing I've read says to use some type of anti seize, but after reading this thread I'm not sure.

[Deadshot2]

The barrel is 416 stainless, the anti seize is Loctite sold by brownells. It cost me $7, no big deal if I don't use it. Every thing I've read says to use some type of anti seize, but after reading this thread I'm not sure.

Anti-seize is a good idea for Stainless. Surprisingly enough the elements added to steel to make it "Stainless" also make it more prone to "galling". It doesn't take much to keep the threads from galling, just enough to coat the threads as they are screwed together. I just put a little on the first couple of threads on barrel or fastener and that is transferred to the internal threads and the rest of the external threads as screwed together. Another popular anti-seize/lube is Aeroshell 33. Again, a small amount.

As stated earlier, "wet" torque values are less than those for "dry". One manufacturer of anti-seize products recommends a reduction in torque of 25%.

http://www.antiseize.com/PDFs/torque_specifications.pdf

As far as friction holding the position of the barrel nut in place, if there is tension the film remaining between nut and action is thin enough to hold nut in place. The anti-seize is merely an "anti-weld" agent that prevents the asperities on both surfaces from welding together when moved (due to the high temps caused at the sharp contact points) with the resultant galling.

[darkker]

No, repeat, no, friction does not secure the barrel. The barrel is secured by tightening the nut, which compresses the nut, the recoil lug and the action; and applies tension to the barrel threads. It is this combination of tension and compression that secures the barrel, and ALL nut/stud combinations.
joe b. The recoil lug may be compressed, but as it floats over the barrel, doesn't matter to the cause. The nut, like all lock nuts, tries to pull apart the action and barrel threads. That fricion of pulling thread against thread, is what stops things from coming loose.

[RustyShackle]

The barrel is 416 stainless, the anti seize is Loctite sold by brownells. It cost me $7, no big deal if I don't use it. Every thing I've read says to use some type of anti seize, but after reading this thread I'm not sure.

So long as it doesn't have copper in it you should be good to go. Copper anti-seize on stainless is a no! Nickel based anti-seize is what you want.

[snowgetter1]

I use two rubber mallet whacks on the barrel nut wrench while I hold the action in my hand. not sure how much torque it is. I use anti seize and have only had a couple of barrels move when tightening or loosening a muzzle brake that was on tight.

[Blackthorn]

So long as it doesn't have copper in it you should be good to go. Copper anti-seize on stainless is a no! Nickel based anti-seize is what you want.

Since this subject has been breached again I am curious. What issue are you afraid of when using a copper based anti seize? Galvanic corrosion? Please elaborate...

[Deadshot2]

Since this subject has been breached again I am curious. What issue are you afraid of when using a copper based anti seize? Galvanic corrosion? Please elaborate...
From a product brochure put out by an anti-seize manufacturer:

First paragraph:
http://www.armitelabs.com/products/CP2000_Copper_based_Anti-Seize.html

Haven't heard of it ever happening on an SS Rifle barrel but on smaller fasteners I've seen some strange breaks.

[RC20]

I hate the copper (stuff is too kind) on general principles.

While not necessarily relevant to the Savage, we put it on shaft to hold sprockets on. Usually with a squeeze hub that the sprocket bolted to ( the hub and sprocket had tapered surfaces, so the bolting squeezed the hub to the shaft)

The stuff welded the hub onto the sprocket. If used with just a set screw bearing or sprocket, it welded them to the shaft.

Never used it for anything again, threw away what we had.

[RC20]

I just torque my switchbarrel barrel nut to 20#. Haven't had any problem with barrels coming loose. Seems to me with a right hand twist every shot is tightening the barrel. Some switchbarrel shooters only hand tighten their barrels.

Not disagreeing that 20 can be effective nor you could hand tighten thought hat seems nebulous on several fronts.

This is a far more complex joint/interface than a bolt that simply tightens into the body of whatever its attached to.

You have a threaded barrel, that is not tensioned by the barrel shoulder itself but by a separate nut. That nut is free to move as its not part of the barrel.

[RustyShackle]

Copper on stainless steel creates an inter-crystaline corrosion, which can make actual stainless steel parts crack and break. This is why the nuclear power plants/ petroleum refineries do not allow copper with any material which comes in contact with the stainless steel parts.

I hijacked most of that description with a simple google search as I didn't feel like writing a research paper on the topic. Basically though it's similar to galvanic corrosion from the electron potential in the dissimilar metals.

[Blackthorn]

I understand metallurgy and what happens when two dissimilar metals are put together. Galvanic action fortunately requires three elements to come together. The most important is a constant level of exposure to water or a corrosive environment which no rifle of mine are exposed to at any real length of time. Otherwise the metals will breakdown at a normal rate which should outlive me.

I also understand the issues that arise from inter-crystallization corrosion that is caused with dissimilar metals under continuous heat (temps of 400-850 degrees Celsius) or during the process of welding. If my rifle were to reach the temperatures over the sustained time frame required to cause inter-crystallization my wood stocks would burst into flames or at the very least my epoxy bedding would melt..

I was curious and got my answer. Thank you for the response.

[RustyShackle]

Yes, fortunately rifles, in general terms, are not subjected to great deals of moisture. However undoubtedly there is some that will travel under the bbl nut where it can become a host for galvanic action. Also copper on various steels and under various conditions has shown to induce stress cracking/embrittlement. There are a handful of mechanisms by which this occurs.
The entire potential for for any of this can be avoided using nickel based antiseize, so I guess you can use whatever you like, but it's cheap insurance.

and I guess I should add that I now just use a dab of white lithium grease for assembly. Just enough to prevent galling.

[Blackthorn]

Better cheap insurance than no insurance. I do agree that nickel would be the best choice when it comes to stainless. I have used copper, black moly, and nickel based anti-seizes when mounting barrels. I cannot say that any work better than another but I can say I have never had a barrel come loose nor removed requiring excessive force.

[Cmgoff]

Errr, what? What are you trying to say with that? I'm an engineer and I think you might have some terms confused. PM me if you want to go over things in a little more depth. Generally speaking nuts,bolts, and various fasteners of similar stature are held tight via friction from torque(compression/tension) between the two mating surfaces.

Typically only 10% to 15% of the overall torque is actually used to tighten the bolt, the rest is used to overcome friction in the threads and on the contact face that is being rotated (nut face or bolt head).

Cheers!
This is an incorrect ststement. I too am an engineer and I also manage a fastener testing Lab. You are correct that most of the torque applied is wasted overcoming the friction forces. The misconception is that friction prevents the joint from loosening. Actually the stretching of the components ( traditionally the bolt but in our case the threads in the nut) act as a spring and keep the joint closed. You could say that the sping applies s normal force to the surfaces and therefore friction is still reasponcible for keeping the joint closed

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