Freezing a barrel ?

[msnations]

strictly mechanically speaking, 'cutting' and 'working' a material both induce stresses. That being said, pulling/pushing a button down a blank results in many times more stress than cutting rifling. stress is a difficult thing to measure, but I am of the opinion that a buttoned barrel has more residual stress AFTER stress relief than a cut barrel right off the rifling machine.

Both flavors of barrel seem to shoot very well...

 

[frankgreen]

Straightpipes, No the cut rifled barrels do not need to be restress relieved like buttons do. We don't here and we didn't at Krieger.

The only real stress I could see us inducing into a blank is during contouring. As long as the blank does not bow the blank is fine.

We finish ream, prelap, rifle and finish lap after turning. Taking a .0001 per pass cut out of the barrel during rifling.

Msnations, Taking a .0001 out per pass how much stress do you think we are putting into the blank? Yes it would be hard to measure. It's not effecting any sizes anywhere that we have ever seen and that's how I would look at it from. Could it be putting some in? Possible but as you stated not like the stress induced by a button. That's why they have to stress relieve after buttoning and before contouring etc....

Again though we never made claims that it helped with cleaning, accuracy or barrel life. In a high quality blank we have never seen it.

Later, Frank

 

[chino1969]

I too have wondered how long will a barrel last before the chamber cracks.

I've examined brand new match grade barrels with my bore scope during break in, after cleaning, etc. The beginning of firecracking depends on the caliber. For example, one of my .243 A.I. barrels began to show evidence of firecracking after only 80 rds. My .308 shows no evidence after 400 rds., my 6mm BR is beginning to show evidence after 400 rds. In spite of firecracking, there is no evidence to suggest the barrel won't continue to shoot. I bought a used Kreiger .22-250 A.I. barrel for $50 and had it re-chambered by the same smith who originally chambered it. This barrel is a hummer.

Lou Baccino

 

[StraightPipes]

Frank Green, so if the barrel builder is on his game from start to finish, the blank "does not" need to be stress relieved. We are building the barrel using the process that is done at the mill, as is the way the barrel builder receives it from his source.
Again, this is for a "cut rifled" barrel only.?

Great info here!

 

[frankgreen]

Straightpipes, For a cut rifled barrel I would say no it does not need to be stress relieved. The material already comes in double stress relieved.

There is more to this and I can write a book on it from what we've seen and learned. Even learned some more things this year.

Give me a call and would be happy to talk about it.

Later, Frank
Bartlein Barrels
262-649-1574

 

[StraightPipes]

Frank Green, thanks for some good solid information. Thank you also for the invitation.

Best Regards

 

[jackieschmidt]

Krieger does an in house cryo treatment to their barrel blanks for one reason, to improve tool life, and cut the bottom line. They say that they have hard data to back this up. From what I remember, they have been doing this in house for some time.

That being said, I chamber both Kriegers and Bartliens, and I cannot tell the difference in the way one, or the other, machines. But then, I am not drilling, reaming, and then rifling a small hole on a long piece............jackie