Checked the Crown today with the heavies. I find that at setting 5, the 34 gr JSB shoots at 790. If I bump it up to MAX, I get 830 fps. And it sounds like the "whoosh" is gone with the heavier pellet. As expected, my holdover @50 is 1 mil compared to dead on with the 25 gr. Also tried the 31 gr H&N and got 870 fps. All these pellets are very accurate. It doesn't seem like the Crown is particular about its pellets.
Crusher