Has anyone used a metal spacer beneath their Scope's Elevation Turret to "rig" a zero stop? I have a Leupold Mark 4 ERT 6-20 with the M5 Turrets (the Mil ones without the zero stop from the factory) and was going to try to put a metal spacer below the turret to make my own zero stop. Think it will work and not screw anything up? Has anyone done anything like this? Thanks for the help.