But it's not all about punching paper. A good rifle, especially if you do not have a gun safe full of them, must perform multiple functions. If you are punching paper AND protecting against zombies, then .223 is still your best option.
If punching paper and wanting to be able to take a 4-footed beast, say in the whitetail category, maybe you should consider .308.
.45acp, .40 S&W, 9mm, .38 Spl, .380 acp, 22lr
12 gauge, .223/5.56x45mm, 30-30 Winchester
2 Chron. 7:14 Christians must seek His face