Just shot my bow through the chrono, and got 270 fps. My Jaguar was set at 70 lbs. and 28" draw length. Arrows were 28.5" long and weighed 425+ grains.
It may not be shooting 300+ fps, but I think 270 isn't too bad(I am not a speed nut anyways). My 2007 Jaguar is rated for 310 IBO.

A.S