243 is a good starting place. With 100 grain Partitions or some of the Barnes bullets, you've got a good combination. It was news to me that you can buy ammunition already assembled, but I suppose that a combination you'll like is commercially available.
Don't neglect the 30-30, using LEVERevolution ammunition. The recoil is relatively mild, and with the new flex tip bullets and the new powder, you get quite a bit better trajectory. It will probably do just fine for you out to 200 yards or more.
I'm also partial to the 260 or 6.5 Creedmoor. Those are mild recoil rounds with very capable performance.
