Lrush, I got my 30P-1 recored to the Ultra 9 internals. I have used it on 28 Nosler and 300 Norma Improved and it works great. Although now that I have my 338 Ultra, I am using that on all of my magnums because it is just so impressive, and it is actually lighter than my recored 30P-1.
When I got my 338 Ultra I was really blown away by the change in recoil impulse. I use my can on 300 and 338 Norma wildcats, and those rifles become much more comfortable to shoot from a recoil perspective when using the can versus the brake. Compared to the TBAC brake, recoil impulse is noticeably longer, and all of the jarring sharpness is gone. There is still a lot of recoil energy there for sure, but it is very controllable. Shooting a big magnum with the Ultra is a ridiculous amount of fun.