Given the .22 Hornets, .22/250s, .220 Swifts and the .220 Howell working here, the bias is rather clear and have never seen any local purpose for the .204.
That is mostly driven by the .17 Remington (700 BDL) I've been using for about 30 years. Flat-shooting as they get, just deadly on small game, easy reloading for accuracy and factory stuff is available if you don't. You might be surprised at how much once-fired .17 Rem brass I picked up at a local range in AZ a while back - still reloading it.
The only caution is when shooting coyotes - especially bigger ones. If one strays and hits directly on shoulder or hip areas, at that velocity some of the better shooting .17 bullets readily will disintegrate on contact with sufficient bone mass. A needless mess. Coyotes are tough animals that can soldier on - so you very well may wind up tracking down a painfully maimed coyote. Not much fun for you and none for the coyote.
For a lighter .17, the .17 Hornet has worked nicely here. I think it is better than the .17 rim fire stuff and most other smaller case .17s. With plenty of brass from shooting the .22 Hornet for 55 years, reloading has been snappy and it doesn't use much powder - and use the same 25 grain bullets. I tend to limit the .17 Hornet to about 125 yards.
No recommendations or claims - just a bit of experience.
