Jon, when you have personally taken well over 3000 hogs with pretty much every kind of weapon legal to take them with you may learn what that protective cartilage "shield" is as well as every other feature of a wild hog. Here is a picture and before you say "that's a fat layer", it isn't.



That is straight up cartilage and it can and will absorb a LOT of the hydrostatic shock from a large metplate bullet especially that of a round ball. Add to that a thick layer of fat on a winter hog and you have a pretty thick layer of resistant and impact absorbing material. Think about the physics of how a bullet works for a minute and you might grasp a little of what I am trying to explain to you.

As far as your question goes, if you think about it, you hit your hog with that .50 cal in the thinnest part of the cartilage right on top of the bone. Hard bone is actually LESS shock absorbing than that cartilage and fat layer is.