I can think of a couple of times when an animal's body position fooled either me or someone in my party to the point something didn't work as it should have. When an animal is facing us or broadside, there's little doubt. It's those obliques that cause problems.

When you're setting up a shot, don't forget that your target is three-dimensional. Your point of aim broadside is going to be different than if your target is quartering toward or away from you. And - don't forget to analyze your shot once the animal is down. Did your bullet enter where you expected it to? Where did it go from there?

There's no reason you should doubt your 7mm RM. While I tend to follow RR's line of thought regarding monolithics and while I save the entry/exit would logic only for bowhunting, there's no reason your bullet shouldn't have done the job, either. Look to your shot. Was it as good as it could have been? We all likely have a story like this one in our past.