I've found that under "average" conditions the .17 Hornet is a 300-yard prairie dog rifle when using plastic-tipped 20-grain bullets. Have also found, after shooting PDs with a bunch of people, that almost nobody hits more PDs than they miss beyond about 300 yards in average conditions. It's also far easier to spot your own shots (whether hits or misses) with the .17 Hornet than almost any other round. The .17 Fireball comes close, and was my choice for most PD shooting before the .17 Hornet appeared, but used more powder, so heated up the barrel far quicker. It got maybe 250 fps more with 20-grain bullets than the Hornet, but I never could tell any practical difference in the field. (Plus, my first Hornet shot a little better!)
Also found that the .204 works just as well on PDs as the .22-250 or .220 Swift at ranges from about 300-500 yards, the cartridges most PD shooters used for shots beyond 300 back when I started PD shooting--again, with less recoil, so its easier to spot your own shots--and with less powder, so barrels don't heat up as quickly.
So that's my pair of cartridges for PD shooting out to around 500 yards--at least until I find something better....
Beyond 500 I use whatever round uses much higher BC bullets. Have used everything from a fast-twist .223 Remington to rounds like the 6.5-06. My latest is a 6XC. But I don't do as much 500+ shooting as I used to, partly because most landowners want PDs thinned out, not trained to duck into their holes at the first rifle shot.
