Just put an UltraDot 30 on my SRH 480 Ruger 9 1/2". After some preliminary adjustments 1 1/4 inch 50 yard group. Used 400 grain cast from Montana Bullet with 17.5 grains 2400, 1008 fps average velocity. Too nose heavy but my Taurus Raging Bull 6 1/2 inch doesn't have scope mounts. How short is too short for RedDot? Don't want to damage optic!