I'd be leery of feeding that thing Kodiaks on a regular basis, that's a heavy pellet for that powerplant, even the SuperMags are a push. Superdomes usually do well in the Gamo's, as do JSB Exacts and Crosman Premier Lights. Don't care much for the Gamo pellets, they tend to be pretty inconsistent in my experience. Although the Kodiaks may group well, they can be tough on stock springs, and don't produce as much power as a lighter pellet moving faster. Best bet is a mid weight pellet, 7-9 gr. in .177 and 14-16 gr for .22, IIRC. HTH.
Dave