Why Cyro Freeze a barrel?????????
Why cyro freeze a barrel, does it increase accuracy, what are the benefits, who does it, how much does it cost? I have ignorance on this and ask for your expertise to bring me into the light. Thanks for any and all education on this!
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It's a good method of releiving or omitting stress post machining. It avoids damage to surfaces but it's expensive and may or may not make any real improvements in the condition of the material. When the Bbl returns to "room temperature" the rigidity (stiffness) is the same. 0 -
Howdy owen,
As xxcross & barz said, and it supposidly works by cutting down the resonance noise, meaning vibrations. Imagine a tuning fork being hit-- it's the vibes that create the tone, well, same with a cartridge fired though a barrel causeing movement, wobble if you will, and the cyro treatment helps dampen that effect, creating a more accurate barrel. Least that's the theroy as I understand it.
45er0 -
Lots of claims, some like it and some think it's a waste of time. When I rebarrel a match gun or for the best accuracy I use Kreiger which have been proven for years to be of highest quality (as well as others). I have spoken with them and they kryo all the barrels prior to machining on them. The claim that their tooling lasts much longer. Also they cut rifle their barrels. 0 -
Just as the stresses remaining in a steel barrel from its creation as a blank through final machining are unpredictable from barrel to barrel, the effects of cryo treatment will also be unpredictable. Some barrels may see a marked improvement, with others showing very little change in performance. It's a crapshoot, but not likely to decrease accuracy. 0 -
Contact Texas Knifemakers Supply (TKS) out of Houston, Texas. They will cryogenically treat knife blades for $15-$20, so they may be willing to treat other items for similar prices. Don't know why not. As I understand it, the process hardens the steel by making molecular changes. And, regarding guns, as I understand it, the process is generally performed on barrels only, but I do not know for certain.
Obviously, costs will escalate depending on how much work a smith does to prepare the gun for cryo-treat (i.e. barrel removal, if that is what it takes).
By the way, I had TKS do an old carbon steel bowie knife blade that the handle broke off on. I sent the bare blade to them to cryo-treat. When I got it back, the knife is noticably easier to sharpen, takes a keener edge and holds it longer.
Whether cryo-treating will make a difference on guns is something I personally do not know. In my mind, however, it makes sense to me logically that it probably makes no difference on gun barrels up to eight inches, but longer (rifle) barrels, maybe so (mitigating a tendancy to flex by making the steel more rigid). Someone with personal experience on cryo-treating guns may wish to weigh in here.
Also, with rifle barrels in mind, this shop I mentioned, TKS, may have a size limit regarding their equipment to perform this process, I don't know. You could check with them or query the web to find a other shop(s) that do this work.
Here is something to read. I would copy/paste this, but I don't want to plagerize, so here is a link to a Wikipedia blurb regarding cryogenically treating steel:
http://en.wikipedia.org/wiki/Cryogenic_hardening0 -
No heat warp.
I purchased for my MR2 a complete set of cryogenically treated rotors (slotted/vented). The claim is that there is an absence of warp.
So, and after about 30k miles, my rotors haven't warped (yet?)..I do a lot of heavy brakeing while going down the mountain road where I live to town to shop.
My read is that cryo-treated steels are much less prone to the problems associated with high-heat, if the cross-reference between automotive applications and firearms useage is valid. Joe0 -
owen219,
Here is an answer straight from a well-known barrel maker with a top reputation:
http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm#deepcryogenic
From Lilja Rifle Barrels, Dan Lilja:
"Q. What is your opinion of the deep cryogenic processing of barrels?
A. The cryogenic treating of barrels at a temperature of -300 degrees below zero has been a hot topic of discussion lately. Our short answer is that it will not harm your barrel but we are not completely convinced of all of the benefits claimed by some. The only benefits that we feel are likely to result from the treatment are possibly a longer barrel life and a slight increase in machinability.
Claims for increased accuracy through stress relief are not founded in our opinion. When barrels are button rifled no material is removed, it is just displaced. This causes stresses to be formed in the steel. If these stresses are not removed problems will result. These negative conditions include warping of the barrel during other machining operations, an increase in the bore diameter towards the muzzle end of the barrel during the contouring phase, and in the extreme, lengthwise splitting of the barrel. Also, if there are stresses remaining in the barrel they can be slowly released as a barrel warms up during firing. This causes the barrel to actually move during the course of shooting, causing inaccuracy.
In our testing we have found that the only effective means to completely remove the types of stresses introduced during rifling are with conventional heat treating using elevated temperatures. The -300 degree treatment alone will not remove these stresses. We have been told by a knowledgeable metallurgist that the deep cold treatment will, at best, remove up to 6% of the remaining stresses in the type of steel used for rifle barrels. The key words here are remaining stresses. In other words if the barrel was not stress relieved conventionally, then only 6% of the original stress will be removed. If the barrel has been treated conventionally with heat and then brought through the -300 degree cycle, up to 6% of any remaining stresses could be removed by the cold treatment. We do know through our testing that the cold treatment alone will not remove any significant amount of stress and that the problems outlined above concerning stress will remain in the barrel.
So, because of the very limited amount of stress that could be removed with the cold treatment (if the barrel has been properly stress relieved with heat as our barrels are) we do not believe that there can be much if any accuracy benefit to the -300 degree treatment of our barrels. It is for these reasons that we feel the cold process has very little potential for increasing the accuracy of our barrels. In our opinion, other than the removal of these stresses, there are no other mechanical factors involved that could benefit accuracy in a rifle barrel, resulting from a heat treating operation, either hot or cold.
For reasons not completely understood however there may be an increase in the wear resistance of the steel. This type of wear however does not contribute greatly to barrel erosion. We invite you to read our comments on this type of barrel wear in the question regarding the use of moly coated bullets.
Another possible side benefit to the freezing process is a slight increase in its machinability.
Post Script: Since I originally wrote this an excellent article by Kevin Thomas of Sierra Bullets was printed in the September, 1998 issue of Precision Shooting magazine. Mr. Thomas found, in a controlled test, that there was little benefit to deep freezing match grade barrels. He could see no difference in accuracy but probably a slight increase in useful life. I would encourage anyone interested in this subject to take a look at this article."
And this from Hart Rifle Barrels:
"Does cryo-treating reduce stress in Hart Rifle Barrels?
Cryo-treating steel has been in practice for many years to reduce stress in metal, and is very effective in some metals. The Crucible Specialties , Inc. 416R stainless steel we use to manufacture barrels is virtually unaffected by cryo-treating. Crucible's metallurgist have advised us that cryo-treating has no effect on 416R stainless steel. We have also independently tested several barrels and have been unable to detect any difference in the steel. We offer this service, as several of our customers believe in it and feel it gives them a competitive edge. The final choice is yours as to whether you feel this service is necessary."
And lastly, this from a Cryo specialist:
http://www.cryogenicsinternational.com/shooting.htm
I don't use cryo treated barrels. I have used some in the past but the results didn't impress me enough to continue using them. Simply buying the best cut rifled barrels on the market makes the biggest difference.
Best.0 -
Thanks so much for your great replys. Great education! owen219 0 -
My two cents worth. T retired from Browning Arms where I was the Chief Firearms Technician in the R&D Division. One of the tests I performed was on Cryo treatment of barrels. Took 3 rifles and fired for accuracy, then sent the barrels to be treated. Fired after treatment, NO BETTER ACCURACY, in fact one shot perceptable worse. The head of the company accused me of falsifying the test. I had no reson to do so and was positively impartial.
Just my experience, but I wouldn't pay good $ to do it.0 -
Please excuse the typos, getting old and it's late at night. 0 -
My two cents worth. I retired from Browning Arms where I was the Chief Firearms Technician in the R&D Division. One of the tests I performed was on Cryo treatment of barrels. Took 3 rifles and fired for accuracy, then sent the barrels to be treated. Fired after treatment, NO BETTER ACCURACY, in fact one shot perceptably worse. The head of the company accused me of falsifying the test. I had no reason to do so and was positively impartial.
Just my experience, but I wouldn't pay good $ to do it.0
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