I have been sighting in my Tracker II 20g using rifled slugs, after researching all the opinions on the web about using cheap rifled slugs in rifled barrels. You should try Winchester rifled slugs and Remington rifled slugs at $8.75/15 at Walmart. I got one dead-on bulls eye at 50 yards, from the bench, no sandbags or rest. I am adding weight to my Tracker II and doing some other cheap recoil reducing modifications, a problem you don't have with the USH. Try the cheap ammo first for your short range shooting, and if it gives a group of 3 inches or less at 50 yards, then go for it and save your money. If you are shooting beyond 100 yards, then give the sabots a try as well.