Still can't follow. How does fps become rpm? Wouldn't you multiply by 60 to get rpm?I can't believe rotations in seconds would remain a constant for a long distance shot.
It might be easier to follow if we used simpler numbers;
If you are shooting a bullet out of a 12 twist barrel (1 turn in 12" which is 1 turn in 1 foot) at 3000 FEET per Second, the bullet at muzzle is making 1 revolution every 12 inches (1 foot). But that revolution is happening in 1/3000 of a second. In one second it will have made 3000 revolutions. In one minute it will have made 180000 revolutions (3000 revolutions x 60 seconds in a minute) and that is revolutions per minute (RPM).
As mathman has said, the spin slows down much more slowly than the forward motion.
