I've made a similar stop out of black delrin that goes between the bottom of the elevation knob & base (for lack of a better, more descriptive term) on several of my Sightron SIII LRMOA scopes. I measured the gap between the bottom of the knob & turret base with the scope set on its 100yd zero, then turned out a ring of delrin of that thickness that is a snug fit around the turret. Remove the knob screw, slip the delrin ring into place, and replace the knob - done. Only bad thing is the ring covers the turret index line, but you should be able to get the knob's zero index lined up well enough without it. Worst case scenario - you're a quarter min off, up or down.