When I was a kid, my Dad and I were deer hunting in a shotgun only area. A nice buck come up through the marsh and Dad cut loose with his Browning 12 gauge Semi Automatic Light 12 shotgun. He was shooting 2-3/4 slugs. It was broadside.
He shot and it kept running. So Dad cut loose again, and once more for good measure. That buck ran almost 100 yards. It was easy to trail, but when we got up to it, all three slugs were behind the front shoulder and you could have covered them with a hardball. The insides were basically not there. How that deer ran 100 yards to this day we still talk about it.
Deer are tough creatures. While they are easy to penetrate, they are not easy to kill as some people think. That is a nice looking bullet actually.