First welcome aboard Hunter! I have not hunted Whitetails with my 7MM RM for the last 10 years! My last experience with the 7MM RM was two bucks with 150 gr. bullets.
The first was dead within sight, but no expansion at about 40 yards. I probably would have had a hard time recovering him if he had not expired within 20 yards of the shot.
Second, was about 80 yards with the same, 150 gr. bullets. This buck ran for over 100 yards, with no blood trail due to again, no expansion. I recovered the buck, probably by pure luck.
Looking back at those situations, I have concluded:
1. High double lung shot, internal bleeding due to shot location. (Deer ribs and lungs don't provide enough resistance to expand heavy bullets!
2. Plain old, wrong bullets for the job!
I believe the 7MM RM, using lighter, 139/140 gr. bullets, designed for more expansion would make excellent Whitetail medicine!