I took a small whitetail with my 350 Remington Magnum a couple of weeks ago. It is pretty well the ballistic twin of the Whelen. I was after elk as well, so I took the 350. I used a Hornady 250 grain RN and the shot was about 75 yards. The angle was slightly uphill, and it entered on a rib just behind the leg, got both lungs and literally tore the heart into 3 pieces, then exited mid rib cage just behind the off shoulder. The deer did one of those "heartshot" dashes for about 15 yards, then piled up. The entrance hole was about 35 cal, and the exit was about 1 inch in diameter. Blood trail was good enough for a blind man to follow on a moonless night.
I figured this seemed to work out quite well, and was impressed. However, I cut my own meat and upon butchering, I found the deer was badly bloodshot between both shoulders and ribcage, and also between muscle layers on both shoulders. This was despite the fact that neither shoulder had been touched by the bullet. Obviously, the hydraulic shock factor on this was tremendous.
I have used this same bullet and load on moose at similar ranges and the bullet held together beautifully, so it certainly did not blow up. In fact, I recovered one on a 120 yard heart/lung shot on a moose and it still weighed 248 grains, but was a perfect mushroom. But this load was apparently just too much gun for the little deer at that range.
All in all, based on this experience, I couldn't recommend the 250 gr Hornady RN as a deer load in a Whelen, although it is excellent for the big stuff. I'm inclined to try some Remington 200 grain PSP CoreLokts next for deer...