hi wrote:ya, and another thing is that maybe at 10 feet away you loose 10-20 fps because of drag. it may not be as much as 20 fps, but maybe 5-10. i have no proof of you loose that much, but its possible.
edit- so the muzzle volocity is not 602, the speed at 10 feet is 602 fps.
I'm a complete novice at all areas regarding physics, but I think it would be even more than just drag which slows down the projectile. A chronograph measures the time which it takes for an object to pass from point A to point B. It then uses this figure as the velocity reading.
However, this number is not actually the muzzle velocity (no matter how close you put the barrel to the chronograph); rather, it is the average rate of change from point A to point B, not the instantaneous rate of change at point A; the latter would be the muzzle velocity.
This idea kind of brings up another question: Is there any means to measure the exact muzzle velocity of any type of spudgun or such, considering that you do not have an accurate formula of the speed of the projectile?
Sorry if this post is kinda random/completely wrong; I was just thinking aloud...