Wondering about Cryo Treatment
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Danny Brooks
Guest
Another cryo shop
Guys,
If you need another choice for getting your barrels cryo'ed, John Myer, Boyce ,Va, 540-837-2598. I just spoke with him and he gets $50 per barrel. He has done several barrels for me in the past, plus built some very good competition guns. Give him a call. He waits until he has enough material to fill up the unit before doing the process.
Danny
Guys,
If you need another choice for getting your barrels cryo'ed, John Myer, Boyce ,Va, 540-837-2598. I just spoke with him and he gets $50 per barrel. He has done several barrels for me in the past, plus built some very good competition guns. Give him a call. He waits until he has enough material to fill up the unit before doing the process.
Danny
Lee Martin
Active member
A
AZUARO
Guest
Dan Lilja lightly talks about Cryo treatment for durability of a barrel but doesn't specifically speaks about accuracy improvements...I haven't found/read any specifics as to its accuracy
potential supported by something like BEFORE and AFTER tests or stats, anyone has done it or has some reliable info?
As mentioned in my other reply: Back in the 80's Cryo was a big thing among shotgun barrels but then after most of the manufacturers started using Chrome Lined barrels the durability was no longer an issue and
this stress relieving process kind of died in that particular shotgun segment.
Stay warm...
azuaro
potential supported by something like BEFORE and AFTER tests or stats, anyone has done it or has some reliable info?
As mentioned in my other reply: Back in the 80's Cryo was a big thing among shotgun barrels but then after most of the manufacturers started using Chrome Lined barrels the durability was no longer an issue and
this stress relieving process kind of died in that particular shotgun segment.
Stay warm...
azuaro
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A
AZUARO
Guest
Dan Lilja & Ed Shilen and about Cryogenic Processing of barrels
This information was taken from Dan Linja and Ed Shilen's web sites and about Cryogenic treatments:
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.
ED SHILEN
Should I "cryo" my barrel?
If you have heard that the cryogenic treatment stress relieves steel, this is false. We have measured the residual stress in 4140 and 416 steel with a process called x-ray diffraction. After much R&D, we have not been able to measure any changes in molecular stress after cryo treatment. For this reason we do not endorse the cryogenic process, but we can safely say that it is not detrimental to the barrel either.
This information was taken from Dan Linja and Ed Shilen's web sites and about Cryogenic treatments:
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.
ED SHILEN
Should I "cryo" my barrel?
If you have heard that the cryogenic treatment stress relieves steel, this is false. We have measured the residual stress in 4140 and 416 steel with a process called x-ray diffraction. After much R&D, we have not been able to measure any changes in molecular stress after cryo treatment. For this reason we do not endorse the cryogenic process, but we can safely say that it is not detrimental to the barrel either.
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R.DesJardin
Guest
The major issue in proving/disproving is that it's a destructive test that can't be repeated. Ever shot changes a barrel. So you can test the same barrel before and after treating. From my talks with barrel makers there is still a lot of mystery why some barrels shoot better than others with all dimensions being the same. I have seen new test barrels not shoot.
I did test a used barrel that was a mid .1 shooter but was all over the place in the wind. It did get better but not enough to jump up and down about. i can say it would be competitive. I did two before chambering and they set records and were a little better than average in the wind. They were very accurate and all are cut rifled and the next ones are done and ready for next year four cut rifled and one button….. we will see……… jim
Lee Martin
Active member
It's hard to question Ed Shilen and Dan Lilja. I've been skeptical of cryo but may give it a try. I have a 6 BR we built in the late 80's and its seen ~15 barrels to date (all Shilen, all premium select). They tend to fade between 800 - 1,100 rounds (same cleaning routine on each). May be interesting to see if cryo extends that window a bit. As suggested though, there are so many variables at play it's tough to draw hard and fast conclusions from a trial like this.
-Lee
www.singleactions.com
-Lee
www.singleactions.com
The better way...
Would be to cryo all your barrels for a while, say years, and compare your results with the non-cryo years. I don't think a close call would be good enough to say either way. It's a close one every time on a single barrel. Read the results above. Some like it and some don't.
Would be to cryo all your barrels for a while, say years, and compare your results with the non-cryo years. I don't think a close call would be good enough to say either way. It's a close one every time on a single barrel. Read the results above. Some like it and some don't.
Let's face reality.
Wilbur,
That's a great idea, however, if anyone out there did this test, it would be moot for many of us.
Why? Many of us (Including myself) don't have many years left.
We have to think more realistically, i.e.: Months, Weeks, even Days. LOL )chill(
Wilbur,
That's a great idea, however, if anyone out there did this test, it would be moot for many of us.
Why? Many of us (Including myself) don't have many years left.
We have to think more realistically, i.e.: Months, Weeks, even Days. LOL )chill(
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JerrySharrett
Senile Member
Cryogenic treatment of steels will get you different results based on the steel and the condition of that steel. For example, high-carbon tool steels get a significant increase in ductility. In several tests we had performed on hss/co twist drill bits, the cryo treated bits would drill 30-50% more holes before needing resharpening.. The workpiece material being drilled was 17-4PH Stainless in condition 1150M. These workpieces were breaker plates that were 1.125 thick and contained 250 1/8" diameter holes each. The test machine tool was a Cincinnati CNC drill, so the application of each drill was constant as to speed and federate. The cryo treatment apparently lessened the drills cutting edges chipping which is the principal condition in drill bit cutting edge failure.
Another test I am aware of, George Kelbly Sr. among other things the Panda benchrest action manufacturer, took a couple of rifle barrels that came off the came piece of barstock and chambered them, then screwed each one on a benchrest rifle. He and Paul Gotshall loaded 500 rounds of PPC for each barrel. They then ran 500 rounds, as fast as they could load and shoot, through each of these barrels. According to George, a borescope inspection showed the non-cryo'ed barrel to have noticeably more firecracking than the cryoed barrel.
As to benchrest rifle barrels performance being improved by cryogenic treatment, I've had a couple of barrels that had what seemed to have residual streses because when rapid 10 shot strings, like shooting an unlimited target with a rail gun, the non-cryoed barrel would start "walking" the group after 4-6 shots. In those barrels I would send them to Cathy Bond in Ohio. After the cryoing of these two barrels, the "walking" stopped. So, it seems that if a rifle barrel has residual stresses that are effecting accuracy, I would suggest getting that/those barrels cryo treated. BTW, neither of the two barrels I had were the same brand and neither was a Krieger. I've worn out a few dozen Kriegers over the years and never had this "walking' problem. Is it because Krieger cryo's their barrel blanks before machining? I have no way knowing for sure. John Krieger, said their primary purpose for cryo treatment was to improve machinability of the barrel steel.
Take all this FWIW but if I have a benchrest barrel that is "walking" groups, I'll gladly spend the $50 or so having it treated.
Another test I am aware of, George Kelbly Sr. among other things the Panda benchrest action manufacturer, took a couple of rifle barrels that came off the came piece of barstock and chambered them, then screwed each one on a benchrest rifle. He and Paul Gotshall loaded 500 rounds of PPC for each barrel. They then ran 500 rounds, as fast as they could load and shoot, through each of these barrels. According to George, a borescope inspection showed the non-cryo'ed barrel to have noticeably more firecracking than the cryoed barrel.
As to benchrest rifle barrels performance being improved by cryogenic treatment, I've had a couple of barrels that had what seemed to have residual streses because when rapid 10 shot strings, like shooting an unlimited target with a rail gun, the non-cryoed barrel would start "walking" the group after 4-6 shots. In those barrels I would send them to Cathy Bond in Ohio. After the cryoing of these two barrels, the "walking" stopped. So, it seems that if a rifle barrel has residual stresses that are effecting accuracy, I would suggest getting that/those barrels cryo treated. BTW, neither of the two barrels I had were the same brand and neither was a Krieger. I've worn out a few dozen Kriegers over the years and never had this "walking' problem. Is it because Krieger cryo's their barrel blanks before machining? I have no way knowing for sure. John Krieger, said their primary purpose for cryo treatment was to improve machinability of the barrel steel.
Take all this FWIW but if I have a benchrest barrel that is "walking" groups, I'll gladly spend the $50 or so having it treated.
Lee Martin
Active member
Jim, I'm not taking a side here nor do I have an opinion on the treatment. I will say Ed and Dan know a hell of a lot more about barrels than I do. But that said I'll try a cryo or two for my own sake.
-Lee
www.singleactions.com
Jerry, I did talk at length about this and that is what led me to do it. The results were the same as George stated, Fire cracking was less and the big one is they didn't walk and that is the big one. Plus chambering is better, if they do that it changed something
Lee, I would try it, i never take anyones word on anything. I need to prove it or disprove it……….. jim
Lee, I would try it, i never take anyones word on anything. I need to prove it or disprove it……….. jim
Lee Martin
Active member
I'm the same way Jim. Finishing up a PPC right now and may have a couple of Shilens cryo'd. I'm eager to see if I notice a difference when chambering.
-Lee
www.singleactions.com
-Lee
www.singleactions.com
Butch Lambert
Active member
I finally found the true stress relief for metal. I put a barel in my lathe. It needs to turn at 725RPM. I take a lead hammer and tap the barrel for about 31.5 minutes. It made a moa barrel into a 1/8 moa. I've been keeping this a secret, but decided to share with you.
You probably wanted to know why I had won so much the past 2 years.
You probably wanted to know why I had won so much the past 2 years.
but my chicom lathe is in metric, I CAN'T GET 725 rpm....... do you think it will be OK to use 722? Should I adjust my strokes? Or my time?
I don't think my time is in metric.
Or maybe it don't matter.
hmmmmm
this is cornfusing
al
Butch Lambert
Active member
Al, I will adjust my VFD and run a test. It may take 2 years to get irrefutable evidence. I know that you are patient and interested in the real answer.