Try a 250 or 300 gr Shockwave with a Harvester short black sabot and 100 - 120 gr. of the powder of your choice. I have had great results with this load out of my Omega. You could also try a 300 gr .430 Hornady XTP with a Harvester Green Crush Rib sabot. I have heard good things about this load and the Omega. I have some but I haven't had the chance to try them yet. One of these loads should shoot very well in your gun. I think you will be much happier with one of these than you were with the powerbelts. Much better bullets.