Game Development Reference
At the 10-meter range shown in Figure 18-1 , we are within point-blank range and the
bullet hole lines up with the sights.
Figure 18-1. Point-blank range
In Figure 18-2 , with the target at 100 meters, we see that for some reason the bullet is
not hitting the target where we have pointed the weapon. At 300 meters, the bullet hole
isn't even on the target. You can see that by simply accounting for projective motion
and idealized drag, we are already having trouble hitting the bull's eye. The process by
which these differences are accounted for is called zeroing the sights .