"Gravity is predictable, the wind is not."Bob
Wind drift is proportional to LAG TIME, not flight time.... The lag time is the difference between the actual flight time and what it would be in a vacuum (ie no drag).... The faster projectile has more drag, and hence a greater lag time, and therefore more wind drift.... Here is a chart for a pellet at 50 yards....and here is a similar chart for bullets at 200 yards....Note you have to push a bullet at 2500-3000 fps to bring the wind drift back down to what it was at 900 fps.... .... We are very fortunate with airguns to be able to operate in the "sweet spot" of velocities right around 900 fps.... Bob
I’m just curious guys if anyone has it in them to add a little more. How does your spin rate decline at a slower rate than your velocity? I know your rpm goes up and down as velocity rises and falls, but isn’t the projectile still spinning the same amount as it was when it left the muzzle? For example a 1:10” twist is still making one revolution every ten inches no matter the speed, or I assume it is. Seems like there would be a direct correlation with speed and rpm. Y’all have forgotten more than I know about ballistics and I believe that y’all are right but I can’t figure it out. Beau
......... Regarding wind drift at 200 yds, it's interesting that the bottom of the subsonic curve moves right as BC decreases in the chart. Thinking of pellets, this could be the difference between a lower BC pellet having increasing drift begin at 1050 fps and a higher BC pellet having increasing drift begin at 950.