cryogenic tempering


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gunner03
February 5, 2005, 01:46 AM
There is a company here in mpls.that claims that this process will improve groups as well as increase muzzle velocity.
See for yourself at www.diversifiedcryogenics.com
Any thoughts?

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BusMaster007
February 5, 2005, 01:52 AM
Cryo + Moly = Bogus... :)

kaferhaus
February 5, 2005, 09:04 AM
cryo treament of barrels has not been proven in any scientific manner to improve accuracy. Any speculation otherwise is just that... someone's "personal" observation.

i believe it's a huge waste of money unless you're the one selling the service....

if it had been proven to be of any advantage, every benchrest shooter in the country would be using it.

these type questions should be floated over at benchrest central. there are several current world record holders who post there on a regular basis. You may be surprised at the amount of BS that floats around here as regards accuracy and accurate rifles.

It's a well known fact among we that have been in the pursuit of accuracy game for many many years that off the rack rifles capable of consistenty shooting 100yd groups in the half inch range are exceedingly rare... many very expensive custom gunmakers willl not guarantee that level of accuracy

yet it seems every joker with a keyboard has a remchester or whatever that's shooting these kind of groups..... nevermind that 95% of them don't have the bench skills to shoot groups of that level IF THEY HAD A CAPABLE RIFLE.

There are many things that affect accuracy some of the basic most important ones are.

the shooter

good barrels (these don't come on factory guns and don't let anyone tell you otherwise)

good bullets (generally well over 20 bucks a box)

a good bench with a good rest

and a couple dozen other things... but if you don't have the first few, the rest isn't gonna matter

Art Eatman
February 5, 2005, 12:09 PM
I don't know zilch about the effectiveness of the process. What I do understand is the reasoning behind the idea of cryogenic treatment: Supposedly, it's a stress-relieving action. Stress-relieving is alignment within the crystalline structure of a metal so that changes in temperature do not lead to internal pressure changes (stress). Pardon my weird little mind, but I guess you could think of it as changing a piece of gnarled wood into a straight-grained plank.

So, if this works, it would mean that the rise in temperature of a barrel during a string of shots would not change anything in the straight line of the axis of the bore.

Like I say, I dunno. Historically, heating to some appropriate temperature and then controlling the rate of cooling to ambient temperature has been the primary method of relieving internal stress in any steel structure.

Personally, I'd tend to go along with kaferhaus' comments, particularly since I vaguely recall Gale McMillan's having made similar comments.

Art

Mike Hull
February 5, 2005, 12:26 PM
Cryo treatment has been part of the heat treating process in custom knives for many years. It adds a couple of points of hardness(on certain steels), and it makes the blade tougher, more resistant to shock, and it will hold an edge longer than a non cryo'd blade of the same steel, all other things being equal.

What that "may" do in a rifle barrel, is make the rifling last a bit longer in certain types of steel, as it would be a bit tougher. I can't see where it would benefit accuracy.

Some steels retain large amounts of untransformed "austenite" after heat treating(a bad thing), and having that piece cryo'd, converts that retained austenite(a good thing). But, to obtain maximum benefit, the piece needs two or more complete tempering cycles. This should all be done at the same time as heat treating, because to obtain the max benefit, it should be cryo'd right after the heat treat quench, and just before the tempering cycles. :uhoh:
You be the judge.

mete
February 5, 2005, 02:39 PM
As a metallurgist I have been involved in questions about Cryo many times. Yes it has been around a long time and we used to call it sub-zero quench.It is useful with complex steels such as tool steels to reduce the amount of retained austenite which barrel steels don't have !!! The idea of stress relieving by freezing is contrary to all the metallurgy books which state something like -stress relieving is done by HEATING to 700-100F. The statements in the Benelli ,website for example, about it are just nonsense[ even though they make fine guns].....Some makers have lots of claims but they are the ones that offer it [Krieger] But others who have tested it carefully have found no benefit. I have read through the websites of companies that offer it and they are mostly nonsense ! If you believe in myths ,$75 will relieve you of your money and anxiety.

BusMaster007
February 5, 2005, 03:39 PM
"If you believe in myths, $75 will relieve you of your money and anxiety."

We could use that line for a lot of things! Good one.

:)

swifter
February 5, 2005, 04:02 PM
I tried it on several rifles -- bargain package -- including one that had me at wit's end for accuracy. (no change... :cuss: ) Two of the lot DID clean easier after cryo. I'll not do it again. :D

Tom

larryw
February 5, 2005, 04:12 PM
I'm not smart enough to know if cryo is art, science or pixie dust. I am smart enough to appreciate the results: I own a light barreled hunting rifle that would change from a 2MOA gun to a >10MOA club as the barrel heated. It suddenly became a hot bore tack driver with no other change but a $40 cryo treatment.

So, pronouncements of this being bogus may be based on science as we know it. But I don't think we know everything.

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