Barrel torque and headspace

[hemiford]

Rem 700, Also Weatherby 9-lug (same threads).

I removed a factory Rem barrel to screw on and headspace a different barrel, but I also want to keep using the first barrel.
The removal torque was astronomical, probably in part due to Rem's thread sealant. But from here forward I want to use
just a little antiseize and much less torque. This is how I would install the new barrel which is new onto this receiver, then
set the headspace. But the old barrel would be seeing a new torque value onto it's former receiver.

How much does the barrel torque spec affect headspace ? Maybe I specify 50 lb-ft, which is "plenty tight", not just "snug" .
I kind of find it hard to believe it would even change by .001", I would think less, but, I do not KNOW.

 

[Victor3Ranger1]

I am not familiar with this stuff but I did just torque a barrel back onto the receiver.
Myself, I feel that 50lbs is too little but I might be totally wrong. I would think that 80lbs or maybe 100 lbs being better

 

[MagnumManiac]

This is a can of worms.
I never torque my barrels above 75lbs/ft on a permanent re-barrel. Many recommend 100lbs/ft, but this often burnishes the barrel shoulder.
With my switch barrels using a barrel vice and wrench, it is nipped up just past finger tight, no torque wrench is used, when the barrel stops, it is tight enough.
You will get many answers here, but when I'm fitting up a barrel for headspacing, I rarely go passed about 20lbs/ft just to run headspace gauges in and check. YMMV.

Cheers.

 

[Victor3Ranger1]

This is a can of worms.
I never torque my barrels above 75lbs/ft on a permanent re-barrel. Many recommend 100lbs/ft, but this often burnishes the barrel shoulder.
With my switch barrels using a barrel vice and wrench, it is nipped up just past finger tight, no torque wrench is used, when the barrel stops, it is tight enough.
You will get many answers here, but when I'm fitting up a barrel for headspacing, I rarely go passed about 20lbs/ft just to run headspace gauges in and check. YMMV.

Cheers.

I am glad you came in.

Good information

 

[Dmagna]

I tighten the barrel to 80. I don't know why I just picked that number. Also make sure to tighten the barrel enough that you don't unscrew the barrel if you install or uninstall a barrel device.

 

[akdad]

On the subject of torque in other areas of tec I'm always surprised how many people don't stop to ask if it's a wet or dry torque or even understand the difference.

 

[hemiford]

On the subject of torque in other areas of tec I'm always surprised how many people don't stop to ask if it's a wet or dry torque or even understand the difference.

Yes, an extremely valid point.

 

[Victor3Ranger1]

On the subject of torque in other areas of tec I'm always surprised how many people don't stop to ask if it's a wet or dry torque or even understand the difference.

I am interested in what you know about this

 

[crashlanding]

I don't know about torquing barrels, but on screws and nuts, always suggested to use lubricant before torquing, I do this on ring to base and ring to ring screws

 

[dfanonymous]

You might as well not even worry about the actual torque value number if you plan to lubricate the threads.

Anyone with automotive skills should be able tell you that there's a difference between dry torque specs and lubricated.

Theres really no good formula for it to get the exact number when wet either. Don't believe me?

Skip to 16:38, or watch the whole thing if you never had to hold the flashlight for your dad.


There's nothing wrong with grease or antisieze if you want to use it. Just know that the torque specs are dry specs. Go hand tight and 1/4 to 1/2 turn more should be fine,

 

[BUSTINDOGS]

You are over thinking this, just saying. You will start peeling threads off the barrel or the inside of the action before you change the headspace.

 

[Beluebow]

Spot torque......torque it until you see spots...then you're done.

 

[hemiford]

You are over thinking this, just saying. You will start peeling threads off the barrel or the inside of the action before you change the headspace.

Oh, I probably am overthinking, at least it's not an unsafe thing to do.

So the threads are 16 per inch or .0625 per thread, so one revolution of the barrel will move it freely 1/16-in.
If you only rotate the barrel 10 degrees instead of 360 degrees (say from the point where it's "tight"),
then, did you only move it .00173 inches ? (1/36 of a rotation) Or did you just stretch the threads ?

 

[VinceMule]

Utah state Benchrest shooter, Steve Hendrey was a tooling engineer at the Jet aircraft repair facility in Ogden Utah. Steve was a master machinist. They found that some barrels resonate to a point where they loosen. Tightening the barrels to 100 fixed a lot of accuracy issues on the custom BR guns. I suspect that 60-75 maybe plenty. Some of the best benchrest gunsmiths torque to 100, and they do put a little lube on the shoulder face which will make many heads explode...these are some of the best benchrest gunsmiths in the world.

There is also much talk on a loose thread for a remington barrel tenon vs one that leans between a class 2 and 3 where Steve was a firm believer in a looser fit for Remingtons.