I remember reading on one of the top custom barrel makers website that they tested cryo-treated barrels and there is no difference between a properly stress relieved barrel using traditional methods, and cryo-treated barrels. Did you have any other work done on the rifle, like bedding, trigger job, free floating, etc...?

I just don't think that the cryo-treatment alone would take a rifle from 5" groups to 1/4" groups without other work... but I could be wrong.

Mike