p-dog,
I agree that over-leading is a tendancy on realatively close shots (out to 100 yds) as we had that occur a bunch during a running target shoot at a recent long range course. The deer target was getting hit in the brisket quite frequently.
I am catching each shot on a 3'x4' piece of plastic cardboard so that I can determine actual lead required at different distances, angles, speeds and bullet velocities.
A few years ago I was hunting caribou in northern Quebec, sitting on a rock near a big muskeg. Caribou were really moving, running on a trail around the far end of the muskeg - 175 yards from us. Saw a nice bull running at a fairly good pace. Asked the guide how much to lead and he said to hold on its' nose. Shot from Underwood shooting sticks, caribou piled up at the shot. After we field dressed him we went back to the rock, another nice double-shovel came running down the same trail, same distance so I held on his nose and repeated the kill - maybe ten yards apart.
Interesting thing was that the guide had no idea where to hold, he admitted he was winging-it. He had never shot through a scoped rifle, particularly something as fast as a .300 Weatherby. PLUS both bullets struck the center of the heart of each bull. Made me look good but I really did not know what I was doing either, other than trying his suggested hold.
Lots to learn about hitting movers, just like learning to shoot at long range.