The 204 case is an improved version of the 222 Rem Mag, 30 degree shoulder, shoulder moved forward and body slightly straightened. So you have to think of the 22-204 as a 222 Rem Mag Improved(not AI'd) it is about as much as you can get out of the .378 bolt face without fireforming or using rare 5.6x50 Mag cases, it has a little more capacity than the 223AI.
Center 222 Rem Mag next two to the right 22-204 picture curtesy of alf
I know what it is, but you can’t tell a prairie dog there is a difference. So the chasing your tail to get no advantage accomplishes what?
A simple question on what to do with a rifle with a 223 bolt face, turns into a cluster&@#% and all the attempts to improve the 223 don’t get you a nickel’s worth of difference, just a chance to look for brass that is hard to find and dies that are harder to find.