To Sam's point.... I shoot an AR squared up, feet shoulder width, right foot slightly back, knees bent, and leaning forward on the balls of my feet. Not the most comfortable shooting position, but helps you move. I'm 6'1" and usually use the the third slot back with a standard M4 type stock or 2 slots back with a padded sopmod type stock. An AK stock's length would probably fit this type of shooting well.