Hey Chuck, good to see you in the BH forum a little.
I'm not sure if you know it or not, but the 300fps is "IBO" speed, which is shot using a very light arrow, with nothing on shaft, strings, etc. Shooting the bow at the highest poundage and draw length. Thats how the 300 fps is acheived. My Bowtech allegiance' IBO is 327-335 FPS "IBO"
With my D'loop, peep, 350grn arrow(which is the lightest i can go) and a 28" DL @ 70lbs Im shooting 297FPS.
And you may know all of this already... sorry if you do
[8D], but in reality, by the time you get your silencers, peep, loop, and total arrow wieght, expecially with a whisker biscuit and shooting at 60lbs, I suspect you would be shooting the250fps range, and that is completley a guess, But with your long Draw length it may be higher.
None the less, still fast enough to kill a deer.