Where you hit 'em matters. A 223 is a fine moose caliber....if you are able to head or neck shoot them with a 55 FMJ or better, and you have a rapid firing rifle along the lines of a AR-15. But there are much better choices.
For lung shots, getting bigger hole(s) out the back side helps to get the lungs deflated. It's the difference between drowning them and suffocating them. Drowning takes longer than collapsing the lungs. Bigger calibers and bullets tend to work better, though expanding solids also make the needed holes, if perhaps not as large.
