Any experts out there, I need some information. I don't understand cryogenic treating a action or barrel! I know you dip a part in, I think liquid oxygen for a period of time and presto it relieves the stresses in the steel, well thats what is claimed or is it just hype? Having a degree in Science with a major in Thermodynamics ( Study of heat ) I don't know how this relieves stress in the grain of the steel, or how it hardens the steel for increase wear resistance. I have asked three Metallurgists this question and with out exception they say it marketing hype. Since there is no state change in the steel I fail to see what is going on. Hear is my question WHAT AT THE MOLECTURE LEVEL IS HAPPENING TO THE STEEL? Or is it we shooters have fallen for a flem flam artist idea for making a fast buck?

While I'm not an expert in Metalergy the benefit of cryrogenic treatments is to " effect a complete molecular change in most alloy steels, converting the retained austenite into martensite (a more refined grain structure, which is more uniform than austenite ).

Ray

Colonel-
Cryogenic treating is very common in high performance engins. I've never been to school for this but I've worked around the Motor shops and you pick up some things.Treated materials cryogenically include increased resistance to wear, greater ability to dissipate heat with some other bennefits. I'm sure that a gun barrel would improve if the treatment it has recieved up to that point is not acceptable. Note that I'm no expert but passing along some past knowledge. I think simply put (for me thats easy) Martensite=hard carbon and Austenite= soft carbon. Please let us know if you try this.

First off, cryogenic tempering is not something you attempt at home. It takes a computer controlled process to avoid damaging the part.

Here are the basics on cryo:

Cryogenic treatment has been around for several decades. It was developed specifically for industrial cutting and grinding tools. It was discovered that cryoed metals possessed greater wear resistence and it also increased the life of the tool (considerable operational savings were the result). In short order, the process was adapted to all types of metal objects from musical instruments, softball (metal) bats, racing engines, gun barrels, knives, and anything else metal you can think of.

Here is the science behind the process - Cryogenic treatment is designed to take ferrous and non-ferrous metals down to -300 degrees F at a controlled and incremental rate. Once this temperature is reached, it is maintained for 18 to 36 hours and then the part being treated is slowly returned to room temperature. Some treatments then take the part to +300 degrees for 3 to 5 hours and returned to room temperature.

The process is designed to complete the austenite to martensite transformation that occurs during heat treatment in steel alloys. Austenite is the soft carbon within metal and the martensite is the smaller and stronger carbon molecule which comprises steel. The concept is, if you can covert most or all of the carbon atoms from austenite to martensite, then the metal becomes more dimensionally stable, stronger, and more wear resistant. The process has been proven to work as advertised. There are tons of scientific articles on the treatment.

That is the science. Now, as with all basic scientific principles, they sometimes do not guarantee results in complicated models like a gun. There is no question that converting austenite to martensite is a good thing, but this does not necessarily translate to a more accurate wonder gun. Here are some observations on the process:

1. The time to cryo a barrel is before it is rifled and contoured. The barrel should then be retreated before the chamber is cut.

2. The end result is a more heat tolerant (stable) barrel. For varmint, bench rest, and high volume shooters, heat stability is a big deal. Cryoed barrels ��seem�� to hold zero better over a wider range of operating temperatures.

3. Many report that cryoed barrels are more ware resistant and seem to accurately shoot 50% to 100% more total rounds before the barrel is shot out. Throat erosion is a measurable benchmark for determining wear resistence.

4. Machinists who cut chambers report that a cryoed barrel cut substantially better than non-cryoed barrels. Many state that they can feel the difference while cutting.

5. My cryoed barrels clean noticeably easier than my non-treated barrels from the same manufacturer.

6. It would be difficult to prove that cryoed barrels are more accurate than non-treated barrels because of the many manufacturing variables from one barrel to another.

7. Cryogenics seems to tune barrel harmonics to a more uniform pattern. This is why musical instruments benefit so much from the process. Relieving stress within the barrel improves barrel harmonics which plays a considerable role in accuracy.

8. Way down on the list of possibilities is the very remote chance that by relieving inherent stress within the barrel, you can cause some very minor warping. If a stressed barrel was cut straight to begin with (75% are not straight), by relieving the stress you can alter the bore. This has never been proven, however, the possibility exists in principle.

My opinion is that the process may refine some accuracy traits within your gun. However, it is not a magic treatment and will not turn a crappy barrel into a bench rest wonder gun. If you start with a premium barrel, there are some desirable benefits. Most premium barrel makers treat their barrels before they rifle and chamber so re-treating is not necessary.

With a factory barrel, you may well be wasting your money. This is because you are treating the barrel after the fact (cutting & chambering). You may see some improvements in a factory barrel, however, the greatest gains are to be made are before cutting begins. At the end of the day, I have never heard any report about damaging your gun by treating the barrel. There doesn't seem to be any real downside.

Web sites:

http://www.300below.com
http://www.badgercryogenics.qpg.com/COLD_11699.html
http://www.diversifiedcryogenics.com

Zero Drift-
Thanks for the sites and info. I do disagree that you need a computer to do this. I beleave I was doing this before computer control. Ahhhhhh.... life before computers.

We have a winnah! I'm a big fan of cryo'ing for the same reasons others have outlined, but mostly the dimensional stability part.

I would disagree only with one conjecture - that cryo'ing a factory barrel isn't very beneficial. It's been my experience that factory barrels benefit MOST from cryo since they generally need the most help. Most match-grade barrels shoot fine either way (cryo seems accuracy neutral) but the marginal tubes really come around as far as eliminating "walking", fouling and increased wear resistance. At least that's the report from my clubhouse/garage.

I may have my toothbrush cryo'ed soon.

Redial

I concur with Redial, except my reason is primarilyy a perceived ease in cleaning. I've solved exactly the same problems with the treatment, but it's not universal. On some guns it made no perceptible difference except the ease of cleaning.

Redial and Bob
I agree that cleaning is much better with this done. I have A shotgun and a rifle done and plan on having the rest done.

In my experience a bad barrel will be improved and a good barrel will not..pretty simple, but has held true so far....

In my case it is usually cheaper to buy a good barrel to start with...Thats why I use Lothar-Walther barrels.

Bought a J&T surplus 24" bull barrel AR15 kit and built the gun on a stripped DPMS lower reciever. Shot about 3/4moa to start and got to about 0.6moa with about 100 rds. Sent it to 300 below to do the Trilax cryogenic process. With nothing but a single patch down the bore, shot 1/4moa right off the bat, and now consistently shoots sub 1/4moa, with a best of 0.08" with Sierra 69g MK bullets. $70 for processing and shipping total. I'd say with this treatment there is only upside, and if nothing at all happens to accuracy, it will still be easier to clean, last longer, and your still out only $70. If you want to know if it works, simply try it. Little to lose. My $0.02

I just did a search on cryo-treating and thought this thread was very informative so....BTT.

ZeroDrift,

Thanks for the very detailed post!