RE: Speed!!!!!!!!
280 is expecting a lot from a 510 grain arrow at a 28" draw. Mine are 500 grains at a 29.5" draw and I'm pushing them at 255 fps out of my Hoyt UltraTech which is plenty fast for an arrow that heavy. Keep your goals realistic and you won't be dissappointed. If you get 250 to 260 fps be very happy.