So here are my numbers from GGDT after I make some modifications and get my pcp pump this is what I got... A muzzle velocity of 781fps combine that with a 185grn bullet and that gives me 250fpe!!! Those numbers are with a 20x1.5 tank filled to 1,000 psi... I am hoping to use more pressuer than that and get a little more kick out of it when the time comes we'll see... GGDT says that with the same setup at 1,500 psi would give me 900fps for an impressive 335fpe!!! wow I might have to try that.