ORIGINAL: Bob H in NH

There is only so much speed that is available, given the current "restriction" of 5 gr/lb, a 400 fps bow is not possible. As stated above (I'd love to see how you calculated it, but it matches what I have seen elsewhere), it is against the laws of physics, UNLESS some new technology comes along that actually creates energy during the shot. Even with a 0% letoff bow, which climbs to max poundage very quick and stays there, it MIGHT be doable, but would be unshootable. You would need to get ALL friction out of the system: calbe slide, axles, string against cam grooves etc. I