I have a 17 Mach IV which is so close to a 17 Fireball, that I guess you could say I have a 17 Fireball. Both cartridges are made from the 221 Fireball case.
I also own a 204 Ruger.
I am not sure what you mean when you ask how the Fireball and the 204 compare. As far as performance is concerned, I feel the 204 handles the wind a little better than the 17 Fireball. The 17 does better than you would think when shooting in the wind, but you do need to be conscious of wind and be ready to allow a little for the drift.
In my opinion, where the 17 really shines is when shooting larger varmints such as rock chucks, badgers, etc. The recoil is so slight that you can see your hits through the scope. Most of the time, the bullet does not exit. All you see is a small drop of blood at the entry wound. If the bullet does exit, the hole is about the size of your little finger. Rock chucks etc. usually die right where they are shot- a little quiver and some tail ringing is generally all you see. Smaller varmints do not fare as well with the 17 Fireball. Critters such as ground squirrels etc. are usually shot up pretty bad. Usually all that is left is the head and hind quarters.
I started using Hornady 25 gr. hollow point bullets. Groups always in the 1/2 inch range. I think the rifle will shoot better, unfortunately, I don't think I can see any better than that. Muzzle blast is very mild as compared to the 204.
The 204 treats rock chucks and badgers about like the 17 treats ground squirrels. If you like puss and gore scattered around what is left of the animal, the 204 is a super cartridge. I have nothing bad to say about the 204 as far as performance is concerned. My 204 is very fussy as to what bullet you use. I tried Hornady 39 gr. bullets. About the best I could do was about an inch group. I switched to Sierra 32 gr. blitz kings. Groups are always in the 1/2 inch area. Some times a little bigger, but most times smaller.
The 204 has a nasty crack to the muzzle blast.
I like my little 17 so well that I do not shoot the 204 a lot.
