Barrels unscrewing from the action.

[DR_2297]

I used to torque everything to 50 lb-ft with lubricated threads… that is until a customer had his barrel come loose when removing his suppressor (by hand). My thought is that the recoil lug had inadequate chamfer and interfered with the radius of the tenon to shoulder transition. That is the only incident I have ever had. Ever.

After that I now make sure that all recoil lugs have ample chamfer on the tenon hole and I moved to 100 lb-ft on any assembly with a recoil lug. I still do 50 if the barrel shoulder registers against the receiver face.

 

[Kracken McGraw]

I used to torque everything to 50 lb-ft with lubricated threads… that is until a customer had his barrel come loose when removing his suppressor (by hand). My thought is that the recoil lug had inadequate chamfer and interfered with the radius of the tenon to shoulder transition. That is the only incident I have ever had. Ever.

After that I now make sure that all recoil lugs have ample chamfer on the tenon hole and I moved to 100 lb-ft on any assembly with a recoil lug. I still do 50 if the barrel shoulder registers against the receiver face.

You mentioned lubed threads. I would think a good anti- seize lubricant would help on keeping one from backing out.

 

[DR_2297]

You mentioned lubed threads. I would think a good anti- seize lubricant would help on keeping one from backing out.

I use a SS never-seize generally.

 

[butchlambert]

I don't like gritty anti seize on my barrels. I just use a light synthetic grease. Never had a barrel get loose.

 

[M-61]

Did your fired brass not measure different?

That’s the right question.
As the ‘ unscrewed’ and you continued shooting what do you think is happening to the headspace?
It’s constantly getting longer. Your brass is stretching but you will not notice hard or impossible chambering because the headspace is growing.
In your case 5 pounds to twist the barrel off is a small amount of headspace increase but it’s probably a right hand twist so continuing would constantly make it worse.
Maybe I misread or misinterpreted your post.
BTW I’ve never had it happen to me and I’m into swap barrel rifles WITH anti seize on the threads so I would question the initial installation torque. Unlike some I rely on my torque wrenches and 50 lbsft on my rifles has been fine.
I’m writing about my Savages

 

[M-61]

You mentioned lubed threads. I would think a good anti- seize lubricant would help on keeping one from backing out.

Actually, no. The anti seize stops the seizure and allows it to (hopefully) always allow removal.
One has to look at ‘Torque Reduction Tables’
Some lubricants require as much as a 50% reduction in the torque as opposed to dry installation. The tables are quite comprehensive and one would be amazed at the reduction stated. Virtually any liquid is a lubricant of sorts. That type results in the reduction percentage. Even Loctite is a lubricant when initially appleid.
I wouldn’t be capable of screwing two dry pieces together. And if stainless steel is involved that is a material which just loves to gall

 

[M-61]

You mentioned lubed threads. I would think a good anti- seize lubricant would help on keeping one from backing out.

Actually, no. The anti seize stops the seizure and allows it to (hopefully) always allow removal.
One has to look at ‘Torque Reduction Tables’
Some lubricants require as much as a 50% reduction in the torque as opposed to dry installation. The tables are quite comprehensive and one would be amazed at the reduction stated. Virtually any liquid is a lubricant of sorts. That type results in the reduction percentage. Even Loctite is a lubricant when initially appleid.
I wouldn’t be capable of screwing two dry pieces together. And if stainless steel is involved that is a material which just loves to gall.

 

[jackieschmidt]

In another thread, it was stated that during the Winter, the two most popular threads were “how do you clean your barrels” and “how do you clean your brass”.

#3 has to be…”how tight do you torque your barrels”

I watched Wayne Campbell Chang a barrel at The Tack Driver, and from the length of the torque wrench, and the click, it looked like at least 80 ft lbs.

 

[Kracken McGraw]

Actually, no. The anti seize stops the seizure and allows it to (hopefully) always allow removal.
One has to look at ‘Torque Reduction Tables’
Some lubricants require as much as a 50% reduction in the torque as opposed to dry installation. The tables are quite comprehensive and one would be amazed at the reduction stated. Virtually any liquid is a lubricant of sorts. That type results in the reduction percentage. Even Loctite is a lubricant when initially appleid.
I wouldn’t be capable of screwing two dry pieces together. And if stainless steel is involved that is a material which just loves to gall.

I understand that what you say is correct.
I have noticed say like on a thread protector on muzzle threads, you can spin it on on off with no lube very easily . When I put choke tube lube(anti-seize) on there it tightens it up and it’s not working itself loose until you make it, when at hand tight.

 

[divingin]

Why aren't barrels threaded and rifling twisted such that torque from the latter tightens the former during bullet launch? Or if they are, why doesn't the torque so imparted prevent a barrel loosening (assuming it was reasonably tight in assembly)?

Inquiring (twisted) mind wants to know.
-

Hah. I see what you did there.

I thought standard barrels were rifled such that the barrel gets a bit of CCW force when fired (from the shooters perspective.) RH twist spins the bullet CW, so the barrel should see CCW force, no? That is the direction of tightening the barrel to the action. Or am I seeing this wrong?

 

[Brians356]

@divingin, standard twist I think will tend to twist the cheek pad toward the right-handed shooter, keeping the shooter "in" the follow-through..
-

 

[6BRA]

Most barrels are stamped with twist and freebore. You would think you would see that stamp moving....

 

[Brians356]

Why don't y'all just use Loctite?
-

 

[Bob3700]

I install my SS barrels with Mobil 28 synthetic grease and torque to 60 ft/lbs. Never had an issue with one coming loose and all spin off with my 3/4" wrench.
I would never use Loctite on a bbl. I ever wanted to take off.

 

[divingin]

Why don't y'all just use Loctite?
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Because it's easier and neater when it comes time to change barrels. No heat or excessive force required; no cleanup (other than a quick wipe with a rag.)

 

[Stumpy1]

Why don't y'all just use Loctite?
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I think someone forgot the /sarc tag...

 

[dusterdave173]

Loctite works--and all you need is the heat from a good cigar lighter to make it release
After one disaster with a factory remington 700 barrel--I noted there was a Ton of Red Loctite from the factory--I had mentioned slight heat to get it off and my smith went nuts like Hell no you idiot! he cut the old ring and ruined a barrel -Trust me the next factory Rem will get some heat and that Loctite will let go--it does not take much heat --no where near enough to hurt an action or barrel if that is even possible. Loctite is great you just have to know how to handle it from start to finish--Never even take scope mount off that was Loctite-- without a little heat from a Bic lighter or some such--
We used to "glue" race car stuff with it all the time--we used easy gentle small amount of heat on anything we were taking back apart just in case--Never an issue

 

[DLT]

I don’t have 1/10 the time or experience put in my rifles as most of you do but I torque nut barrels at 55ft lbs it’s been several now and none have worked loose, YET. The way nut barrels gets installed I wondered if they would stay tight. So far so good

 

[Dave M.]

I wish I could say it's never happened to me but it has, and what happened to you WAS EXACTLY WHAT HAPPENED TO ME on every detail. Even the part about figuring the barrel was bad and swapping it out only to find I didn't need any wrench to take it off, it just spun right off. I'll be honest that before it happened I had a habit of using a standard socket bar and just snugging the barrels down pretty hard by hand and I swore that kind of thing would never happen to me. Ever since that event I now use a proper torque wrench and hit 80FT/lbs every time and it's never happened since.

I use 110ft-lbs and this came as direct advice from a top notch smith we all know very well.
Dave.

 

[TTE]

HOLY SMOKES ! ! ! !

I never even knew that was a thing.