Realistic Ballistics

Overview

Most 3D shooters have hitscan projectiles.  The fact that developers use hitscan bullets is often because, at close range, the delay is unnoticeable and it saves a lot of processing work to calculate the trajectory of these bullets.  A few attempt to add some realism in that regard by using realistic ballistic trajectory for their bullets.  One such game that is famous for this is ARMA 2, where sniping requires a lot of skill and prediction due to this feature.
 

Variants

Early 3D shooters who used this feature only used non hitscan bullets and simulated only the bullet's travel speed, but never simulated the bullet's drop or even the wind effects, however some recent games like ARMA 2 fully simulates projectiles trajectory like the bullet's drop in regards to the range we between us and the target. But in 1998 Delta Force who used a Voxel Engine managed the ballistics pretty realistically, also the bullet trajectory was visible through the tracers