I'm on record as preferring JSB and H&N ammo. I have lots of pellets all the way from Air Arms and Beeman to Vortex and Webley that I use when I get a new gun and, yes, some of them are VERY picky. (I even have a "Frankengun" that likes Daisy!) But, invariably, every rifle shoots the JSB and H&N stuff consistently well.
NOTE: slugs are not recommended for use below 26 joules (18.44ft-lbs). Best results are at 40-60 joules (29.5-44.25 ft-lbs).
Mondo