I have a 17 Mach2 in a G2 carbine and I kill CA ground squirrels out to 200yrds routinely. I recently shot a blacktail jack rabbit in the head at 190 yrds. At close range the little v-max is very explosive, at long ranges it just kills squirrels and rabbits dead. The 17HMR with its extra speed should be fine to 250yds on Jack rabbit sized game on down. If if is windy though, the little bullet, definitely gets blown around and your accurate range will be greatly reduced.
I know the HMR is a little bit loader, but with the Mach2, you need to check the cartridge to see if the bullet is gone if you are wearing ear protection. The gun doesn't even move, it is really amazing. I thought about picking up a 17HMR, but with the mach2 and a 22 Hornet, that is a very small gap to fill.
I would recomend anyone with a contender get a 17 rimfire of either variety, they are just way too fun to shoot.
Good shooting,
Brian