Steve,

I would prefer the .223 Remington myself, simply for logistical reasons, because there is no guarantee that the WSM cartridges will be on the market in a few years, and if discontinued you have either a useless rifle or a very expensive to feed rifle.

Also something to consider if it isn't too hard to feed in Australia...I think CZ 527's are available chambered in .22 Hornet and if you aren't limited to the two choices you mentioned, my preference for a .22 centrefire would be the Hornet.

Richard