This should keep you out of trouble 'til the bird season wink

David J. Compton, “An Experimental and Theoretical Investigation of Shot Cloud Ballistics”, 1996
http://discovery.ucl.ac.uk/1382490/1/396689.pdf

E.J. Allen, "Approximate ballistics formulas for spherical pellets in free flight", 2018
https://www.sciencedirect.com/science/article/pii/S2214914717301459