Milehighshooter
AH enthusiast
Your idea of the 6x45 would also work as well as the mentioned 22 centerfire cartridges, but with the ability to throw a bigger bullet. Depending on the rifle you choose, you may be limited to 85gr bullets due to magazine space. Not a bad thing though, a hunting partner of mine uses the Sierra 85gr bthp in his 6x45 and has handily put down several deer. A 75 gr AMAX may open better and vaporize the birds and monkeys