Barrel treatments have the potential to improve accuracy but are not a guaranteed cure. Here’s the chilling truth about cryogenic barrel treatment and fluting.

by Joe Carlos

I’ve mentioned many times how disappointed I was in the accuracy of the National Match Service Rifle uppers I inherited when I came on as the Armorer for the Army Reserve Service Rifle Team. Only 39 of 135 uppers would shoot MOA. My purchase budget was very limited so I had to use plenty of elbow grease and ingenuity in finding ways to shrink group sizes. And I wanted to get the guns shooting better with a minimum of delay. While this was a challenge, cryogenic barrel treatment made its contribution.

None of the barrel extensions were properly stabilized inside the upper receivers so the backs of the barrels moved around from one shot to the next. This was common in guns of the era. In order to fix the problem the guns had to be stripped down and rebuilt from scratch, procedures I covered in, “The Relationship Of Barrel Extension Diameter To Accuracy In The AR-15” (March and April 2013.) There were other problems like gas tube to float tube contact as well as handguard end caps rubbing against the backs of the front sight housings. These issues were going to require detailed disassembly and adjustments and I knew many of the barrels were coming off their receivers. None of the barrels in question had been fluted.

My budget allowed eight barrels cryo treated for the purchase price of one new premium barrel. Very few of the barrels were shot out and I hoped that cryo would be an affordable repair option. I matched and labeled the barrels to their receivers as I took them off, making sure the guns were put back together with their original parts and retested with the same ammo lots to confirm what the cryo treatment accomplished.

Read more in the September 2016 issue.

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