Best results , well ...

Let me rephrase that , from what i've seen, ONLY the JSB's group well at longer ranges. Keep the JSB's at around 275-290 m/s .

The exceptions are some type of RWS solids that are shot by ridiculously expensive high power air rifles.

I've tried literally every pellet at longer ranges, some with a much higher quality in finish and weight consistency, but they still group like rubbish compared to the JSB's .
Not sure why, but if i had to guess, JSB has their softness of their lead just right.