My Gen2 likes almost anything I load so long as it has a domed tip. Kodiaks, Sniper Mags, Mediums, Lights, JSBs in every flavor, Crosman Premieres, Skenco NewBoys, RWS Superdomes, and Coal Fenix domes. Ixnay on the Kodiak copper and Predator GTAs, though. Crow Magnums are heavy but shoot well enough to 35-ish but start opening up. Not tried Polymags but I dunno if they even fit the mag. If I slow the Forti down I bet RWS Meisterkugelns, SIG, the H&N WC, and of course JSB wadcutters will come into their own
Superdomes are grouping tightest right now with JSBs inside my margin of error (meaning my mediocre skill level). Sniper Lights and Mediums are comparable to the CP domes (as expected since both types are harder pellets), while the NewBoys, Kodiaks and Sniper Mags are a little too loopy for the HST setting but lob accurately enough for 40-yard plinking. Coal Fenix domes were tested only because no other domed pellets kills pests as well.