Here are some speeds from my new tall brace height BK:

Bow maxes @ 61.5# at measured 28.5" AMO (on my scales), the factory specs were 61.2# @ 28" (322 fps with 300 grain arrow)

334 grain arrow = 303 fps

382 grain arrow = 285 fps

432 grain arrow = 271 fps

526 grain arrow = 247 fps

At the lighter arrow weights, I was picking up 1 fps for every drop in arrow weight of 3 grains. To get the arrow down to 300 grains for IBO, I would expect about 11 extra fps which gets me to 314. This is 8 fps less than the birth certificate, but I have a string loop and peep on the string.

When I shot it at 60# along side my DC Patriot turned down to 60#, the BK averaged 6 (heavier) - 8 (lighter arrow weight) fps faster with similar arrows. The Patriot has an extra 1/2" of draw length going for it.

FWIW, I rechecked my dually Patriot on another scale and was able to get it to max out at 71.5#. It shot 355 grain arrows at 308 with string loop and peep. That is pretty close to its birth certificate of 312 with 350 grain arrows.