I like to try new things from time to time. Becuase of this I have used a small variety of projectiles to kill deer. Among them have been 30-06 jsp, 270 jsp & ballistic tips, 30-30 jsp, 50 cal round ball, 50 cal maxi ball and maxi hunters, 54 cal round ball, 54 cal maxi ball, 430 xtp, 452 xtp and 452 hard cast, numerous broadheads.
This is my observation. Deer that have been hit in the vitals, with anything, do not necessarily drop when hit. They often times do not even seem to have been hit and can go several yards before even leaving a drop of blood. I had one yesterday go close to 50 yards before she left any blood and very little of it at that. I almost lost her but kept trailing. I found her over 75 yards from where she was when I shot her. When I field dressed her, her heart was burger. It was a comlete pass through with a .430 240grain, xtp
Deer that are shot and the projectile has hit bone go down NOW. We're talking a spine, shoulder, or hip shot. With a hip shot, they will try to get back up, be prepared for a follow up.
Neck shots. The deer go down immediatly. They can get back up though if the spine has not been hit. I hit one there the other day with a .270 w/silvertips. Dropped like a rock, got up and went to the bottom of a hollow. Left a good blood trail though becuase the juglar was severed.
Sometimes when you shoot, the deer drop even with a complete miss. Graybeard mentioned this. Can't explain it, but it does happen.
Bottom line? I'm not sure. I do believe that shot placement is of the utmost and be prepared to track. Don't blow any shot off as a miss. A lot of my complete misses have ended up with meat in the freezer. Some of my sure hits have ended up with an empty field tag. I don't trust projectiles to expand anymore. A lot of times they just don't seem to work as advertised. I am leaning more and more towards a hard cast with max meplat.