7MM RM 140 grain canon?

In 05, at last light, I took a shot at a German Shepperd sized deer. Of course, If I had a means to compare the size to anything I would not have wasted my time to take a shot at this supplemental tag deer.

The deer went down to eat and the shot entered through the top to the right of the spine, didn't move an inch. But what an amount of shock to this small animal, a great deal of the side where the bullet entered was just wasted.

This last season, went out and picked some 140's ballistic tipped bullets for deer, keeping my 160s for Moose and Elk. Well, them itsy bitsy 140's are leaving more damage than the 160's did. I mean, even on entry, they just seem to be blowing up on impact. What's going on? When the entry area has more damage showing than the exit wound, it goes against anything that I thought a bullet could do. I'd like to see a CSI show on this one. To me, it defies all logic.

So what's going on?