I have been thinging about something that is miles away in my project but not so far away as to not think about it.
In games like cod etc you dont have to think about bullet drop.
bullet trajectory using a raycasting modelling is one way ( raycast from one position to another if the bullet is still under xx distance then raycast again and angle it down), but while this is nice in theory in practice you will be unable to calculate sufficient factors to get to a realistic result. I am thinking that it is best to use a gravity with each bullet that is fired to pull the bullet downwards say setting a weight to each type of bullet (5mm, 7.5mm or larger for sniper).
We have a power amount in the weapon editor so we can calculate velocity and distance but adding x.xx amount of gravity to a bullet would allow the bullet to drop, and emulate bullet drop.
This brings me to another thought leading a moving target with a shot, I guess this would be a raycast and calculating bullet velocity and target distance...
Hmmm the second part was me thinking aloud lol...
Its still food for thought because it would be a great addition to the weapon editor to allow gravity to be set for bullets so people have the choice of setting bullet drop without having to write code (great for artists)..
Let me know what you think.