I'd be interested in how mag primers work in the 204. That's a pretty small case and a very light bullet. I wonder if mag primers might unseat the bullet? I don't know if it would be a real concern or not. I haven't tried any powder besides Benchmark in my Ruger m77. It LOVES Benchmark. 1/2 MOA or less, consistently.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.