Pete,
Others have sort of said it already, but I'll second the motion: It's all about "felt recoil" and how you hold the rifle up to your shoulder. The biggest complaint (as a NRA Certified Instructor) I get from women & kids shooting a rifle is that it's "front heavy". I watch them very carefully and I think that they let it droop and the butt plate comes slightly ajar from their shoulder or pocket in the arm just prior to ignition. You can spot this by watching them and seeing where the holes in the paper are. If they trail in a downward direction with successive shots, that's the big clue, especially if you know that the rifle is sighted-in the for 10-X Ring. The pain causes flinch, and the flinch means that they droop it even more in anticipation of the pain of recoil. So it's a snow-ball effect. Take that "weird" crescent-shaped butt plate out of the equation, and it's much easier for them to handle hunting charges. The shotgun-style butt is easier for them to handle and less "strange". Meanwhile, as an Instructor, I still have to teach them to overcome the desire to stand with their weight on their back foot. Transferring some of the weight to their front foot makes recoil more comfortable, but is hard for them to do if the rifle is too "front-heavy". So it's a combination of things that have to be learned that we all take for granted.
Now IF you're teaching using a curved butt stock, my advise is to use reduced charges and something that's not front-heavy, like a Seneca in .45 cal. As an Instructor, I've noticed that smaller-framed folks tend to group their shots better, and the groups hit the center of the paper, when the rifle doesn't "droop". Upper arm strength and body mass play a part in all of this too. Some folks are just "Naturals" and can pick up a Hawken-style rifle and hit the X-ring.
Hope that this helps.
Dave
NRA Instructor