This is straight from the brenneke web site.
Question: What happens if I shoot your slug in a rifled barrel?
Answer: All our slugs can be shot from rifled barrels. No problem at all. Normally you will achieve even higher precision from a rifled barrel than from a smoothbore barrel. Groups of under 4" at 100 yards are no problem from a rifled barrel with our normal slugs.
However, we have two specialists, slugs designed for use in rifled barrels only: Gold Magnum, a 13/8 oz slug and our SuperSabot, a 11/8 oz expanding (up to 1") brass slug. These two products provide maximum accuracy (under 2" groups at 100 yards) from a rifled barrel, at ranges of over 100 yards.
http://www.brennekeusa.com/Bass pro has the hornady sst for 9.99 a box,I think i'm gonna try those first anyway.Some pretty impressive numbers here:
http://www.hornady.com/story.php?s=148