I am an occasional high power shooter, marksman classification. The biggest barrier to my improving is poor performance in prone slow fire. I always seem to have trouble getting into a stable and comfortable position - particuarly the position of my head. I always wind up with my face too close to the rear sight (with an AR I get dings in my glasses from the rear sight) and the angle of my head is all wrong so I am looking out from under my eyebrows like that guy in the latest starwars movie. Somehow I need to get my face facing up more at the target. What is this? Flexibility problem? Or maybe something wrong somewhere else in my position that is putting my head in the wrong place?