anyone tested the new improved jsb king heavy with tee marauder?

Did anyone test the new improved (thinner skirts) JSB KING HEAVY 33 grain pellets in the benjamin marauder ?

I would like to know if they are any good and at what speed. I would like to test them myself at around 850 FPS but that will require a heavier spring. To make this happen i would expect the 25 grain pellet to do about 1000 fps.

Regards and good shooting,

Jan Peter