As Flannelmeister says, the real sweet spot for the gun is between 750 and 780 fps with JSB Exacts. This will result in a more accurate gun, and that is more important than absolute power when hunting. My old HW35 only pushes out 10.5FPE and it still has enough power to take vermin at 40yd.
As well as JSB, many Weihrauch guns also like H&N FTT - worth giving them a try to find the most accurate pellet.
Get plenty of practice and make sure you can shoot consistent 25mm kill zone size groups at your hunting range before you go bashing those bunnies.