for my pistols i use jsb 4.50 (yellow tin) rifle pellets.
slightly heavier than the pistol pellets and better for 20yd or 25m disciplines; so i am told by the steyr technician.

if the pellet falls through the barrell try the next size up.

to be honest i would chose h&n finale match, but the jsb's are much cheaper and i am not good enough to notice the difference!

bench tested jsb's at 20yd and 10 out of 10 pellets all went through the same ragged hole. good enough for me .

try not to get caught up in the pellet testing trap!

stick to a good make and practise.