Bear in mind that RRA, and any of the cryo treatment facilities that offer this, are trying to sell you something. To the best of my knowledge, the testing that I did with this some years back was the most extensive and rigidly controlled evaluation of these claims ever done. Identical Hart barrels from the same run, all chambered by the same reamer, same smith at the same time, and all broken in for some 300 rounds before firing ten, ten-round groups @ 200 yards from a machine rest, with ammunition all loaded from the same lot of bullets, from each of the four barrels. Total of four barrels involved here, each with that first ten group series being used as a baseline. All four barrels were given to my plant engineer, who then sent all but one out to different cryo treatment facilities. I didn't know which one had been held back and was being used as the control barrel. When the others had all returned from cryo treatment, I fired a second series of ten, 10-rounds groups, exactly the same as the first. All targets were recorded and filed, with the averages of all groups in the documentation. No real differences were observed between the initial series, and the second when the barrels (except the one control barrel) had come back from cryo treatment. I then placed all the barrels into our standard QC firing rotation until each hit 1,000 rounds. At that point, all were given a repeat of the ten, 10-round strings, 200 yards, again, from the machine rest, with all groups documented and recorded. The barrels were returned to rotation and again pulled when they completed 2,000 rounds, and again at 3,000 rounds. The barrels were checked with a bore scope for any obvious signs of wear or other visible problems, cleaning routines were identical in all barrels, etc., as close as we could possibly keep them. Around 3,000-3,500 rounds is normally where we'd lose a 308 Win barrel, so the final series was when things got interesting. Still no signs of major accuracy degradation at 3,000 rounds, but all four started dropping off shortly after that. Typical stuff, occasional flyers that blew a group, with the flyers becomeing more frequent, and slinging the bad shots further from the center of the group. All were retired for failing to meet my regular acurracy requirement somewhere around the 3,500-3,750 round mark, just like the hundreds of other 308 Win barrels I've shot out that weren't cryo treated. And still, at htis point there was no way I could have possibly guessed, much less flat out told you which of the barrels were treated, and which one wasn't. They all went out within a few hundred rounds of each other, which means they were statistically indistinguishable based on performance. We normally saw this much variance between barrels, and it amounts to nothing more than normal variation between barrels and stell based on the hundreds of very minor little details we're normally happily oblivious to. I wasn't until I turned the results over to Ted Lancaster (then plant engineer, and a very sharp guy) that he let me in on which was the control barrel and which ones were treated by who. All tolled, the test consumed four different barrels, some 17,224 rounds through them, and some 2,400 rounds of test ammo loaded from the same lot of bullets, primers, powders and cases that constituted the control standard for the accuracy tests. I wrote this up shortly afterwards, and it appeared in Precision Shooting magazine. Frankly, those were the last cryo treated barrels I messed with, fully satisfied that they don't live up to the claims made for them in respect to the barrel life, cleaning or accuracy. I DO believe that the grain structure is modified to some degree that allows for better machinablity, and the cryo treatments are used in both aerospace and automotive fields (among others) far too widely to be dismissed for those applications. But for what we do, no, it's a waste. Save yourself the money and put it towards something that's actually going to help.
