I have a slugmaster. It likes Brenneke KO Sabots and Winchester BRI style sabots very well. I have enough to shoot this year. Went to D icks the other day, saw Federal Fusion slugs for $9.99. They are rated for 1600 FPS, and should shoot well in the Slugmaster. I have not shot them but I'll probably be going to them next year.
I would not mess around with rifled slugs. Here's last year's Slugmaster buck. No monster, but he looked good the day I spotted him bedded right next to the tree I planned to stand by for a while on a stillhunt.
09 buck pdf.pdf