RE: sighting in a scope
First , if your having that much trouble , make sure all of the screws for the scope are tight. Start out at 25yds to get on paper. Then when your on @ 25 move out to 50 , then when your on @50 try a 100yds. I assume you have a rifled barrel if your using sabots correct ? If you have a smoothbore and shoot sabots they'll be all over the place. Smoothbores take rifled slugs and the adjustments on the scope move the crosshairs , not the scope. Hope this helps.