HI Dave this one is for you LOL I did not want to hijack the other thread !! LOL
You seam to be the technical guy about spin and bullet length so can you tell me this one please thanks.
You have a 40 cal bullet .408 x 430.9 grains x 1.4185 long moving at 1235 fps
will this be stable and what are your calculations and thoughts thanks looking forward to your reply take care
For distance implications you need to calculate dynamic stability (once you have confirmed if your bullet is gyroscopically stable).
Dynamic stability is dependent on center of gravity of your bullet and nose shape which changes the yaw angle and increases the bullets susceptibility to wind drift.
However increased velocity stabilizes the yaw and 1300 to 1400 fps is usually sufficient velocity to compensate for velocity losses over longer distances.
So with slow moving black powder bullets drag is important over long distance since drag can reduce velocity and impact the yaw stability so the bullet starts to tumble before reaching the target.
Pointier bullets have the center of gravity further back so they have more of a yaw angle which requires more velocity to stabilize them and they are more critical to velocity losses over long distances due to drag.
Money bullets are a bit more pointier than Creedmoor style bullets and I have found they lost their dynamic stability in my .40-65 at 500 yards if I am below 1250 fps.
Going over 1250 fps allows me to stabilize the yaw of my Money bullet out to 1,000 yards.+
