There's a lot of info available on the net about cryo freezing. I searched for scientific articles so I wouldn't be hearing promotions from the various companies that offer the service.
Here's an older article.
As to whether it works or not, I don't know. I do know that if the user believes it works, then it does!
It's been my observation that confidence is important, if you can gain confidence by freezing the barrel then freeze it.