speed isnt necisarly it when it come to long range competitions.
the 22ppc 6mmppc and a bunch of other long range benchrest comp calibers are slower than the other calibers used for everyday hunting and varmiting, but these are just as at home varmiting and deer hunting as anything else.
ive actualy got an infatuation with the ppc calibers, ive done some research on them. these calibers were developed in lab for acuracy, they werent designed to kill varmits or big game.
i know im throwing calibers at you left and right, there are just so many choice. but being as that you want to varmit and bench rest shoot id shy away from the heavy kickers like the 308 or 300win even though they do very good in the competions
http://www.reloadbench.com/cartridges/22ppc.html
http://www.reloadbench.com/cartridges/6ppc.html
http://www.reloadbench.com/cartridges/6mmr.html
http://www.reloadbench.com/cartridges/243.html
the main page more info than we ever realy need to know on all these calibers. theres info on facotry and a ton of wildcats.
http://www.reloadbench.com/cart.html