Game Development Reference
shows a rifle and scope combination that is mounted perfectly parallel. Ignoring all other
factors for a minute, we see that the bullet will never hit where the scope is pointed. It
will always be a few centimeters low.
Figure 18-3. Zero-elevation scope
By adjusting the elevation control of the scope, we can make the rifle hit where the scope
is pointed. (See Figure 18-4 .) The range at which the bullet will cross the line defined
by the scope is called the zero range . If a target is at the zero range, you simply point the
crosshairs and pull the trigger.
Figure 18-4. Scope with elevation
If we remove the target and graph the trajectory, it would look something like
Figure 18-5 .
Figure 18-5. Ballistic trajectory
Here we can see there is a second point in which the bullet will cross the line made by
the scope's crosshairs. This is called the far zero , or second zero . This is generally where
the thing you will be shooting at will be. This diagram is often available from ammu‐