I've only ever chronographed 2 loads from mine: 24 gr. 296, CCI 350's, 240 gr. Sierra JHC = 1550 fps.
Corbon Factory load with 300 gr. XTP = 1385 fps. I never buy factory ammo, but I won several boxes of this years ago.
These loads were shot in a 7 1/2" 83.