I had the same problem with the 245g powerbelts,they shot great through my Kodiak but were junk in my Optima.Was shooting 100g Pyrodex.I switched to 240g T/C Mag Express Sabots with 100g of pyrodex and it shot great 3in groups at 100yds like it so much didnt even take the Kodiak out of the cabinet this year.Give it a try should be great for you.