After reading the thread on moly coated bullets and how it may have been a fad that ran its course I couldn't help but think about cryogenics. Will this process fall into the same category as moly or is it acutally a worthwhile process that has merit?

Don't hear much about it any more! I suspect that you are correct, it was a fad.
Peter

The real problem with these things is that if the improvement (value) is small, it's not likely to be clearly seen. IMO this is another non-value or small value item that will disappear slowly as it adds costs and has undocumented returns.

Many other items such as much of the case prep items will also evaporate someday as they too generate such little return that it's hard to justify the tools and time to do it.

Among the few late developements that have proven value is the BOSS system Browning bought out.....and this too is loosing acceptance as folks just don't like the looks and the value isn't as great as it needs to be.

Also of valueis "short cut" from Hodgdons and this one ishere to stay.....clear advantage and no extra cost.

Depends on what you expect from the cryo treatment. It usually will NOT turn a "dog" into a "prize pony" no matter how done or by whom.

On the other hand, some folks like Jack Krieger cryo every single barrel they make before they even deep drill the hole which will become the bore.

Why? Because it relaxes stresses enough to allow more accurate drilling. Krieger told me at the '98 SHOT Show that the use of cryo cut the number of blanks he has to scrap by 7/8ths!! That is, for every 8 barrel blanks he had to scrap after drilling before he started using cryo, he now only has to scrap 1.

Anyway, Jack suggests TWO cryo treatments...one you get for free because he does it to EVERY barrel, to save himself time and money. The other he recommends after the barrel is finished, but he doesn't do that one unless the customer requests it, and then he charges them for it.

Cryo has also long prooved itself in the area of increasing the life of metallic parts. In the Alberta oil sands operations by the major oil companies, they use gigantic drag lines to strip-mine the sand so the oil can be extracted from it. One of the reasons that process is so expensive is that the sands literally grind the teeth off of the drag-line buckets. Nothing keeps that from happening, but cryo treating the teeth does about triple their life.

For a hunting rifle barrel, neither stress reduction nor extended life may be worth the cost of cryo. But, for other shooting applications, it may well be worth the cost.

Guess that is something best decided by each individual customer.

Anybody else have any thoughts?

One of the men in the US who did the first cryo work in this country decades ago was also the man who taught me thermodynamics. He was referenced as an authority in our text book, and the old USSR based their entire cryo program on his work, if that gives you any idea of what Dr. Barron knows about it.

When I went back to engineering graduate school was at the same time the cryo fad was ramping up in the shooting world. I already knew over 90% of what was written was pure BS. Some true facts were stated, but gun writers who could not work a partial differential equation were extrapolating from a couple of true and isolated facts and applying them to things entirely out of context. It was laughable to someone even of my limited knowledge. I brought Dr. Barron a lot of articles and asked him waht he thought. He literally laughed out loud and said something to the effect of, "Wouldn't it be nice if even some of that were true!?!" Tool wear and barrel life are two entirely different matters. If you draw free body diagrams of both it is instantly obvious. Something that works in one application may not do anything at all in the other. Totally different mechanics involved and it is not safe to extrapolate data from one medium to the other.

Many people without a solid background in science and engineering spent a lot of money of cryo equipment and must recoup their costs, so the advertising hype continues to this day.

I worked with a MS metallurgist during the height of the cyro craze. I asked him what benefits it would offer for a shooter. He said none that he could think of.

One of my buddies is a Benchrest shooter. He had a barrel that after it warmed up shifted POI a couple tenths and then it was a hummer. He sent it off and had it cryo'd and it didn't have the POI shift. He placed 2nd at the world championships a few years ago with the cryo'd barrel.
I had a Factory Winchester M-70 375 H&H that would two out of three shots in a group in one hole but the third would be 2" away. The shot out might be any one of the three shots. I had it cryo'd and the rifle settled down into a 3/4-1" rifle. It wouldn't put 2 in the same hole like it did before but was more accurate overall.
Another buddy had a Rem 700 rebarreled with a Shilen Match barrel to 7-08. It was about a 1/2" rifle until he had the barrel fluted. It started shooting all over the place 2-3". He sent it off to be cryo'd and it became a 3/4" or so rifle.
These three experiences lead me to beleive that Cryo'ing can settle down a barrel with some built in stresses from hammer forging, fluting etc.. I couldn't document barrel life or cleaning advantages but I do think that Cryo is a usefull tool.........................DJ

As a knife maker I decided to try Cyro on my steel.I had it Cryo`d before grinding(I use the Stock removel method)and after heat treating.The most noticable improvement was with Damascus Steel.It holds an edge longer now.So I do it to Damascus ,but not High carbon Stainless.I have had it done on Rifle barrels,but can`t honestly say I saw any difference after the treatment.I think That Krieger is right on in doing it before drilling and after its done.If there was any improvement to be had,that would be the method.Just my opinion. OB

Marc,

Will you please do us the service of revealing cryo's actual benefits? For instance, I would not aniticipate any hardening effects to be surface treatment, but rather a work hardening throughout the body of the metal. Also, is there any benefit as a "uniforming" process of stress relief? That is, will the barrel be straighter after machining or react differently to temperature after cryo treatment?

Thanks for any insights that you may offer.

It is best suited to increasing the edge toughness and wear resistance on cutting tool. This sounds like it would also increase barrel life to a lot of people, but it has not been proven to do so, and in fact it is a different application. But if you have an end mill and you want it to stay sharp and cut longer, cryo treatment will help. There are other things, but that is the main one I can remember right now, just after waking up.

I believe that it is corrosion that eats up barrels, not erosion. People can make a case for either one, but I feel strongly that it is corrosion.Either way, cryo won't help extend life.

One thing that really irks me is when gun writers say it "stress relieves" barrel steel. YOu must increase the temperature to stress releive. Dramatic cooling actually induces compressive stresses to the steel. They have it ass backwards and have convinced a lot of well-intentioned readers it is so.

One good thing is that cryo won't hurt anything. So if it makes you feel better, do it and be happy. A key part of good shooting is voo doo anyway-seriously. If you think cryo helps your barrels, then by all means do it.

One comment I remember reading back when this was the hot new thing was that it would decrease barrel fouling and would make cleanup a lot easier. Any thoughts on that aspect?

quote:

Originally posted by Marc_Stokeld:
It is best suited to increasing the edge toughness and wear resistance on cutting tool. This sounds like it would also increase barrel life to a lot of people, but it has not been proven to do so, and in fact it is a different application. But if you have an end mill and you want it to stay sharp and cut longer, cryo treatment will help. There are other things, but that is the main one I can remember right now, just after waking up.

I believe that it is corrosion that eats up barrels, not erosion. People can make a case for either one, but I feel strongly that it is corrosion.Either way, cryo won't help extend life.

One thing that really irks me is when gun writers say it "stress relieves" barrel steel. YOu must increase the temperature to stress releive. Dramatic cooling actually induces compressive stresses to the steel. They have it ass backwards and have convinced a lot of well-intentioned readers it is so.

One good thing is that cryo won't hurt anything. So if it makes you feel better, do it and be happy. A key part of good shooting is voo doo anyway-seriously. If you think cryo helps your barrels, then by all means do it.

Excellent post!!

The only thing I know that is traditionally cryo treated is ultra precision Gauge blocks typically accurate to +- .000002.....( two millionths of an inch) People that work in such increments are convinced that this stabilizes the steel and I'm sure not going to argue as the best I've ever worked to is .0001.....a long ways from millionths.

As far as I know, barrels are not this well controlled (millionths) by even the best barrel makers either.

This has bee discussed here and many other places .As a metallurgist I have read extensively and as far as steel we know it reduces retained austenite which isn't a problem with barrel steels anyway. NRA has found no benefit . Some of the top barrel makers found no improvement .Krieger makes lots of claims but he also has the equipment .On another forum a metallurgist in the business and a member of the ASM committee was given all the opportunity to come up with hard scientific evidence - he couldn't !!! So , for me , it's wishfull thinking !

Well my $ 0.0025 worth of input . Can't hurt to cryo , is it better ?. To moly or not to moly ?. It's like Cut , Buttoned or Hammer forged barrels .

NASA ; Does it for some parts , does it work ?.Yea
Now Rifle barrels ? well that's another log on the fire isn't it !.

The statement made by a previous poster . Don't expect a Nag to be transformed into Thoroughbred is true !.

Shoot Straight Know Your Target . ...

quote:

Originally posted by Marc_Stokeld:
It is best suited to increasing the edge toughness and wear resistance on cutting tool. This sounds like it would also increase barrel life to a lot of people, but it has not been proven to do so, and in fact it is a different application. But if you have an end mill and you want it to stay sharp and cut longer, cryo treatment will help. There are other things, but that is the main one I can remember right now, just after waking up.

I believe that it is corrosion that eats up barrels, not erosion. People can make a case for either one, but I feel strongly that it is corrosion.Either way, cryo won't help extend life.

One thing that really irks me is when gun writers say it "stress relieves" barrel steel. YOu must increase the temperature to stress releive. Dramatic cooling actually induces compressive stresses to the steel. They have it ass backwards and have convinced a lot of well-intentioned readers it is so.

One good thing is that cryo won't hurt anything. So if it makes you feel better, do it and be happy. A key part of good shooting is voo doo anyway-seriously. If you think cryo helps your barrels, then by all means do it.

Very informative post, Marc. Thanks mate.

Before we get too far into damning cryo as having no effect on stress relaxation, and gun writers as ignoramuses, I am not sure we are talking apples and apples here, but maybe apples and oranges?

The Cryo "treatment" which was originally asked about is viewed by some as being JUST the "freezing" aspect of a Cryo "cycle". I am certainly no metallurgist, but it is my (perhaps incorrect) understanding that a "proper" cryo treatment involves both freezing and heating cycles of the object being treated....and that both the low and high temps, and the soaking periods of the objects, vary acording to the metallic content.

I can see how the heat application could relax stresses after the freezing aspect did whatever it is that it is supposedly doing.

But, if one is just talking a portion of the process, such as the freezing, well, all bets are off.

I know for certain things it works just dandy !.

How ever I'm in Chemistry not metallurgy so I Can't say for sure . I borrowed the below statement from a Real BIG Well known Company !.

For steel, the goal for cryotreatment is to convert austinic steel into martinsite steel. Martinsite steel is an extremely hard steel, however, with when hardness increases, brittleness increases as well. Typically, Martinsite is formed by heating austinic steel to elevated tempatures (over 700 degrees) and then quickly cooled to room tempature (quenching in water is one way) Bring the metal to even lower tempatures (cryo treatment) causes remaining austinic steel to convert to martinsite. This rapid cooling causes internal stresses inside the metals microstructure. Martinsite by itself is a worthless material because of how brittle it is. However, when martinsite is heated up again to elevated tempatures again, but this time, slowly cooled, the grain structure become substantually finer and the ductility and toughness increases dramitically, however hardness is slightly lowered.

Shoot Straight Know Your Target . ...

During the barrel build, it is heat treated, and quenched afterwards. A cryo quench at that point is of some value, maybe.
I have that done to my knife blades, and it is supposed to be good, according to the heat treat house.
But, to cryo quench after the barrel has been fitted to an action I consider smoke and mirrors.
I did ask Jim Hart, of Hart Rifle Barrels, about it, and he said that he couldn't see that it would be of any value for their barrels.

Don

Jim Hart?

I spoke to a very respectable person in this field yesterday at a party . We had quite the conversation on several items !.Metals ,EDM chamber fusion , plastics, coatings , vapor deposit and so on !. No wonder the ladies left us by our selfs !!!.

His thoughts were ; " I can't see where it would show any measurable gain in that particular attempted treatment !. Such a slight advantage would be made that one would be better off saving their money towards the purchase of an additional accessory or new barrel !."

I take his word as gospel on such matters .

Shoot Straight Know Your Target . ...