I've been shooting Core Lokt bullets for many years. Once in awhile I'll get a through and through with seemingly no bullet expansion whatsoever. The wound just doesn't bleed much, if at all. Maybe it is my bullet placement, maybe it is the bullet.
All around it is a good bullet, it seems to put them down OK, doesn't tear up a bunch of meat or fragment bruise excessively. Just every once in awhile I get the same size hole exiting as I do entering and no blood.
Some years back I shot one in the snow, it was getting dark. It was standing behind a weed grown barbed wire fence. I picked a gap in the weeds and shot. Took off like it was never hit and actually ran right under my high seat. No blood, a whole bunch of tracks from other Deer, I figured my bullet hit something on the way to the Deer and I had a clean miss. I eventually gave up and figured I'd bring the dog back in the morning. I started up the truck, turned on the headlights and my Deer was laying maybe 45 feet in front of the truck.
Sometimes you need a little luck, skill isn't enough.
I'm really not all that good of a tracker, but I am kind of obsessive and stick with it way longer than most people would. I've found a lot of game other people gave up on.