Loose barrel

[joeb33050]

The barrel on my Striker got loose. The barrel is a 22-250 sporter cut down to ~ 16.5", muzzle filed flat and bore chamfered with an RCBS "cricket". I got home after shooting and found the barrel loose. I've made over 100 barrel changes on the Striker, M10 and M12. I use synthetic motor oil on the barrel threads when changing barrels, and store barrels with this oil on and in the barrels. I never rush when changing barrels, won't allow anyone to talk to me then, and am very careful. I have no idea why this barrel loosened. I now have added a "barrel tight?" step to my every-5-shot gun/scope check.

joe b.

[Deadshot2]

Heating/cooling cycles are notorious for loosening any threaded device unless it's under a lot of tension. Expansion when fired (albeit very little, there still is some) also contributes to this possibility.

Might be a good idea that when you torque the barrel nut you put a "witness mark" across the nut, extending a short amount onto action and barrel so you can just glance at it to see if it matches up on both ends. If not, nut/barrel is loose. A black sharpie for stainless finish and a Silver marking pen for a setup that is a darker finish. If you torqued it, put the line from barrel to action, and all lines up, your GTG.

[Bigeclipse]

Heating/cooling cycles are notorious for loosening any threaded device unless it's under a lot of tension. Expansion when fired (albeit very little, there still is some) also contributes to this possibility.

Might be a good idea that when you torque the barrel nut you put a "witness mark" across the nut, extending a short amount onto action and barrel so you can just glance at it to see if it matches up on both ends. If not, nut/barrel is loose. A black sharpie for stainless finish and a Silver marking pen for a setup that is a darker finish. If you torqued it, put the line from barrel to action, and all lines up, your GTG.

this is exactly why I use a torque wrench and tighten close to Savage guidelines of 70-75ft pounds (I typically go 60ish). Many people said "oh that is way to much" and 30-55ft/lbs is enough. I cannot believe people say this. I think 50-60 is ok but for me I will never go below 60. There is a reason savage chose the number they did.

[darkker]

Wet thread torque and dry are never the same. Maybe just didn't quite have enough vinegar that day?

[J.Baker]

Well for starters, stop wasting the motor oil on them - it's not needed and offers no benefit, and could ultimately be the cause of your problem. Many oils, especially synthetic oils, have additives designed to bond with the metal to make it slicker to reduce friction. Yet here you are using it in an instance that relies on that very friction to secure the barrel.

[joeb33050]

Well for starters, stop wasting the motor oil on them - it's not needed and offers no benefit, and could ultimately be the cause of your problem. Many oils, especially synthetic oils, have additives designed to bond with the metal to make it slicker to reduce friction.

I use CARQUEST full synthetic SAE 5W-20 to clean barrels with cast bullets, with jacketed at cast velocities, steel protector and all lubrication of all parts of all guns. Someday the quart will be gone.


Yet here you are using it in an instance that relies on that very friction to secure the barrel.

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.

[sharpshooter]

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.

Tension and compression = friction. Without friction on the faces, the nut won't stay tight.

[joeb33050]

http://home.jtan.com/~joe/KIAT/kiat_1.htm

[RustyShackle]

http://home.jtan.com/~joe/KIAT/kiat_1.htm

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!

[Captain Obvious]

Tension and compression = friction. Without friction on the faces, the nut won't stay tight.

http://home.jtan.com/~joe/KIAT/kiat_1.htm

You can lead a horse to water...

[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.

[hereinaz]

I bet it is the oil. There is no necessary purpose for using it on your assembled guns.

Sent from my SM-G920V using Tapatalk

[RC20]

There are really only two reasons a fastener comes loose.

Lack of torque.

You are into the plastic range. In this case short of the nut going (its possible) the barrel threads can be stretched into plastic.

If you toque it good and it repeats, replace the nut.

I advocate use of a torque wrench. NSS gives what I feel is a good minimum figure of 50 ft lbs.

Barring that, then the nut wrench with a breaker bar with a bit of effort into it.

[RC20]

NSS lists 50 (max) for the Barrel Nut torque with their tool. They also have anti seize for a lubricant and that needs to be kept in mind.

Dry is one thing, lubricated is another and not a clue what good Savage uses and how it affects the equation.

At a guess 50 with lube is equal to 60-80 dry.

[Bigeclipse]

NSS lists 50 (max) for the Barrel Nut torque with their tool. They also have anti seize for a lubricant and that needs to be kept in mind.

Dry is one thing, lubricated is another and not a clue what good Savage uses and how it affects the equation.

At a guess 50 with lube is equal to 60-80 dry.

savage supposedly uses anti-seize lube. Yeah but are they posting that due to the fact that their tool adds leverage into the equation? If you position your torque wrench at a 90 degree angle to the tool it should take out most of the added leverage. I still stand by what Savage uses. I think they probably go a little overboard probably because of their lawyers but still...if they say 70ft/lbs is safe then that is close to where I want to be. None of this 35-40ft/lbs some people are doing. this is not the first time I have heard of a switch barrel loosening up on these forums and id be willing to bet they were torqued to 35-45ft/lbs.

[J.Baker]

savage supposedly uses anti-seize lube.

NO THEY DO NOT!!!!!

One ignorant individual on the internet who can't tell the difference between tumbling media residue and anti-seize makes that ridiculous claim and now I'm apparently doomed to an eternity of trying to set the record straight. After all, we all know that anti-seize has tiny little spherical balls in it that act as miniature ball bearings - right? SMH!


Not directed at you Bigeclipse, just tired of bad information like this being perpetuated when there's not an ounce of fact or truth to it. You're just an unknowing victim of it.

[Bigeclipse]

NO THEY DO NOT!!!!!

One ignorant individual on the internet who can't tell the difference between tumbling media residue and anti-seize makes that ridiculous claim and now I'm apparently doomed to an eternity of trying to set the record straight. After all, we all know that anti-seize has tiny little spherical balls in it that act as miniature ball bearings - right? SMH!


Not directed at you Bigeclipse, just tired of bad information like this being perpetuated when there's not an ounce of fact or truth to it. You're just an unknowing victim of it.

actually yes they do

[J.Baker]

actually yes they do

Actually - no they don't. Thanks for proving my point about ignorant individuals spreading bad information though.

1. I've toured the factory
2. I've built my own rifle in the factory
3. I'm in direct contract with people at all levels at Savage - engineers, customer service, quality control, sales & marketing, etc.
4. I've asked several of those folks this very question, and EVERY TIME the answer has been the same.


Do you see a tube or tub of anti-seize at this work station? Nope - because their wasn't any.

Attachment 3115

Attachment 3116

Attachment 3117

The gal in the photos above is one of the "swingers" at Savage, the name of the position of those who mate the barrels to the actions. The first photo shows the barrel clamped in a pneumatic vise where the nut is screwed on, then the action is screwed on, the headspace is set and the nut is torqued to spec. The second photo shows the barreled action in a cradle with a mic measuring runout on the barrel. The ram is used to tweak the fit of the action to the barrel to eliminate any runout. The last photo is Fred (sharpshooter) headspacing the barrel on the rifle he built while we were there in the same pneumatic vise that's shown in the first photo.

And this last photo is of me shooting the rifle I built that day in Savage's indoor R&D range.




Now tell us again how Savage uses anti-seize on their barrel threads...

[m12lrs]

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.

[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.

[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]

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.