Got a Hatsan 125 yesterday, anyone know some good pellets?

Got a Hatsan 125 yesterday, and the Crosman Hollowpoints are shooting one hole at 15 yards, but open to about 4-5" at 50 yards...
I'm going to order some JSB Diablos, 18.3 Grain, some H&N Snipers, and some Crosman Premiers 14.3 grain... Any other pellets I should try? 
Thx...

BTW, I already cleaned the barrely, and put 500+ shots through it... Yeah... Bought 750 pellets, and almost cleaned both cans out... Haha