Not sure over killing a deer is a big concern to me. I enjoy a variety of rifles and the 243 and 30-30 have taken their share of deer. At one point I was going to go with a 6x47 the 223 one for a minimal deer rifle, if I did it now it would be the 6x 6.5x47 Lapua or similar. This would be more for fun than a critical need as I currently use a couple other 6mm cartridges on a regular basis and 22s some too.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli