"Ballistics: Theory and Design of Guns and Ammunition" by Carlucci et al. is (from what I can tell - again I'm just a hobbiest, it's the book I work from most) a thorough yet accessible standard work on this topic, detailed in the mathematics, lots of references, covers most of the details that matter, yet 'practical' - you can tell the authors were in the military where they had to produce results and not just papers. I'm not 100% sure how to exactly classify the approach in terms of mathematics. It's basically just 'over the next 10 cm, the bullet drops this much, yaws this much, rolls this much, ...' etc, so basically just incrementally calculating position. Very 'primitive' from a math point of view, but that's exactly what I found interesting - how a brute force numerical approach is considered superior to an elegant closed form solution.

Edit: I should add that part of the reason for this is that some of the external forces on a bullet are non-continuous, like wind coming around a building. That sort of pesky real world effects makes elegant solutions a lot more difficult.