I shot one deer with the 223. Small buck, 45gr TSX. Hit rib going in and out. Lodged under skin on off side. Deer went about 50 yards. Lungs pretty mushed up.
I would think something heavier would be better choice for deer.
My #3 likes 40 and 45 grainers, so that is what I used and I will reserve it for varmints in the future.
jmho
Tim

"The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
Albert Einstein

At Khe Sanh a sign read "For those who fight for it, life has a flavor the protected never knew".