What Makes a Rifle Barrel Accurate? by Daniel LiljaResidual stress in a barrel is another possible cause of inaccuracy. Stress can be caused by the rifling process, as it is in button rifling (our method), or can exist in the steel bar as it was received from the steel mill. We stress relieve our barrels with elevated temperatures. As discussed elsewhere (FAQ) we have not found that the deep cyrogenic process is very effective at removing stress in the steels commonly used in rifle barrel manufacture. [Daniel Lilja]
From www.shilen.com FAQShould 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.