RE: What caliber for deer hunting
.243 is probably the most accurate gun out of the box. Extremely flat shooting and has good BC and SD.
You can shoot 55 gr bullets for varmints, and go up the 100 gr. for deer, elk or blackies. Well capable of 400 yd shots for deer and varmints, blackies I would keep it under 200 yds.
check out my threads on the .243.