My first deer rifle was a Ruger 77 in 6mm Remington Back in the day when some of the gun writers touted the 6mm Rem. as the caliber for the 'One gun hunter'. It was considered better than the .243 since it could hold a little more powder. I was never disappointed ... coyote to deer. The 6mm Remington never caught on, so I'd go for the .243 for a first rifle choice.
When the number of people in institutions reaches 51%, we change sides.