Several powders work really well, but my CZ likes RE-7 and shoots so well, I refuse to look at any other. I've standardized on one single load for every bullet from a 37 Calhoon to a 50 grain VM, I use 18.5gr. of RE-7, for ALL those bullets.
No, velocity is better from other powders, but accuracy is the name of this rifle, and it likes RE-7 best. Other powders that shoot well in the Fireball (according to Foxhunter, over on saubier.com, include Lil Gun, 1680, VV-120, 2015, 4198(take your pick) and probably some others. Hornady says H335 gives top velocity with 50s, but since my little stinker shoots that Reloader Seven so well, I've never gotten round to trying the others. Lil Gun is good stuff, but pierces primers in my CZ, it gets GREAT speeds, but won't work in the rifle.
A buddy of mine has done more with his Remington Classic than I can do with my CZ, but I like my rifle better.
I can't seem to get Foxhunter's data to go from Word to here, so I'd suggest you go over to saubier.com, and ask Foxhunter to post it (he's done so a zillion times, it's kind of a standing joke
![Very Happy :D](./images/smilies/icon_biggrin.gif)
over there). He's ALWAYS willing to help out, he's a fine feller. He's now got a .204 identical to your rifle, too...............
Build a man a fire, and he's warm for a day. Set a man on fire and he's warm for the rest of his life!