What ever caliber you choose, put a SIMS pad on. It makes a BIG difference.

Option #1: As stated above the 270 or 308. Both great choices with a SIMS pad.

Option #2: As stated above, get something like a 30-06 and use the reduce recoil ammo and a SIMS pad. Supposed to be enough power out to 200 yards. You can then use regular ammo once you heal