Furthest I got in university was
Linear Algebra. I do have a degree
Few Americans earn. It is boring
as hell.
I have written Diff EQ algorithms
for my previous employers.
But the mess you print out
means nothing without defining
your variables.
To use the equation, you must fill in the variables as they are ever changing.

Type, length, weight of bullet, barrel twist, length, scope angle, line of sight, humidity, temperature, altitude other atmospheric conditions, gravity, Transverse Moment of Inertia ....
Never mind.
This algorithm is based on the McDrag work done by Robert McCoy.
You may find what you seek there.