I have a Savage ULW 223 that is a shooter. These came with a 1-7 twist. I have all the parts for the swap, but I'm thinking of having the barrel rechambered in 22CM. I should be good on the twist, but the barrel is only 20". Would it be annoyingly loud? I have read about guys with SBR using linear compensators but have never heard of them on a bolt rifle so that might just be dumb.

Thoughts? I haven't tried 70+ gr bullets in the rifle as it sits. While I love to tinker, I might be over thinking this.

I have not done a 22 Creedmoor yet but probably will next build. With your 223 you already have a very capable round, I think it could go up to 80 grain bullets.
The Creedmoor would only be a gain for shooting unknown distances or to launch even heavier bullets. If for deer hunting I would pick the Creedmoor even though I have used a 223 enough to know it is a capable deer round. The Creedmoor would be a good pairing with the 223 and as a back up for when the barrel goes. But I wouldn't get the Creedmoor expecting a huge increase in performance, it has it but it will be hard to see in the field at typical ranges. Extended ranges yes you would see improvements in windage especially.

The more I think about it, and seeing the idea written down, I like it less and less. I figure with all the extra powder in a 22CM they would really shine in a longer barrel. Bad idea, stick with what works.

22 Creeds work in everything from a 16” to a 26”. 20” wouldn’t hinder in the slightest.