10x, your description of mule deer behavior dovetails with what I have seen. I have had multiple deer walk to within 25 yards of me while squirrel hunting. I actually got within 25 yards of a few does early on the morning of my hunt but did not know.they were just over the top of the ridge I was climbing until they took off. The hard part in Colorado is getting a tag where there are enough deer.
I was interested to read about your experience with penetration. How hard was your boolit on the shot in the rear end? Is that a round or flat nose design? I don't know if I had material expansion, but I definitely had a lot of.shock/energy transfer from the big meplat.