Trajectory
The curved path of a projectile in flight, and by extension the table or chart describing it.
Also called Drop, Zero
A bullet begins falling the instant it leaves the barrel and never stops. Because the sights sit above the bore, a rifle is aimed with the barrel tilted slightly upwards, so the path crosses the line of sight twice — once close in, once at the distance the rifle is zeroed for — and runs above it in between.
Everything about that curve depends on four things: how fast the bullet starts, how well it holds that speed, how high the sights sit above the bore, and the air it is flying through. Change the zero distance and the whole picture changes; change the altitude and it changes again.
The solver behind the charts on this site integrates the equations of motion directly rather than interpolating a published table. It does not model spin drift, Coriolis effect or aerodynamic jump, because this site does not record the inputs those need.