I attempted to install my Leupold Mark 4 bases onto my LH Stiller Predator short action receiver and the screw holes in the rear base do not line up with the action. The front base holes line up with the action. I compared the same rear base with a Remington LH short action and they appear to fit. Were the holes in my action drilled improperly or does the Stiller Predator action require some other brand of bases?