Another thought... The "rifle" or crescent buttstock was, I was taught years ago, supposed to be fired between the ball of the shoulder and the biceps, resting as it were against the upper arm, rather than on the torso in "the pocket" formed by the ball of the shoulder and under the clavicle.
I've heard the same thing stubbicatt, but I could never make myself try it.
I had a friend that had a 50/110, he was the one that told me that.
I can't imagine him shooting the rifle that way, he was not a very big fella.