I don't own a USH but would love to have one. Make sure your mount and rings are tight. Other slugs you might give a try are the Lightfield Hybreds. Actually after I made sure all your optics are good and tight I'd go buy a box of every different sabot your local store sells. Set up your target at 25 yards and shoot for a group. Don't touch the scope. Once you find the sabot that shoots the best then zero your scope in. I have three different slug guns and they each shoot different slugs the best.