Depends on the range, the weight of rifle you want to carry, and (of course) your budget.
17HM2 out to 100+/- yards, or the 17HMR out to 150+/- yards, or either the 204 or 223 for longer ranges.
Prior to getting my RAR-P in 204 I had had three or four different 204 Remingtons and Savages, but I wasn't a fan and found a reason to rebarrel them. Then, I got my RAR-P and found that rifle to be so accurate and so easy to shoot that it has made me a fan.
That said, components for the 223 are less expensive and when you're shooting pdogs in volume, less expensive is never a bad thing.
