CrowRifle,
Have tried a friend's VarTarg, and it's a nifty little cartridge. I would definitely choose it over the .221 because of the velocity it can get out of 32-grain bullets, which helps considerably within the 300-yard range where the vast majority of small burrowing rodents are shot. The Vartarg and the .17 Fireball shoot noticeably flatter than the .221, which even in these days of laser rangefinders makes hitting tiny targets out to 300 much easier.
But the .17 Hornet gets just about the same velocity with 20-grain bullets as the Vartarg gets with 32's, and does so using about 2/3 as much powder as any of the .221-based rounds. Plus, I can easily dump 100+ rounds in a shirt pocket when doing a walkabout.
The other thing I like about the .17 Hornet is brass is abundant and cheap. In fact, factory ammo is often on sale for such a low price I can't handload it any cheaper, and is incredibly accurate in my CZ. The brass then costs about half as much as .221's.
