Doug M.
Member
5.56X45 (the proper chambering of an AR platform) with the more dense service type loads will do fine for deer if you do your part, and assuming it is legal in your state. If you are not comfortable or legal, the same rifle with a 6.8 upper (I advocate BCM, for lots of reasons) will do all you need, although at the bottom (hunting bottles and rats) with wither caliber is a bit much.
I'd be inclined to a .22 LR for the rats and bottles, and a medium caliber (.243/.270 size, not more than .308) in a bolt gun for any other hunting up to and including deer. Within realistic performance parameters, placement and proper bullet will be more important than caliber. With my distance vision and a decent scope, I'd be really disinclined to a shot more than 100 yards anyway, I think ... your mileage may vary.
I'd be inclined to a .22 LR for the rats and bottles, and a medium caliber (.243/.270 size, not more than .308) in a bolt gun for any other hunting up to and including deer. Within realistic performance parameters, placement and proper bullet will be more important than caliber. With my distance vision and a decent scope, I'd be really disinclined to a shot more than 100 yards anyway, I think ... your mileage may vary.