direct fire

artillery fire aimed straight at a target

In the context of warfare, direct fire means aiming through a sight directly at the target. This sight may be open fore and back sight or optical. There are two dimensions in aiming a weapon:In the horizontal plane (azimuth); andIn the vertical plane (elevation), which is governed by the distance (range) to the target and the energy of the propelling charge. The projectile trajectory is also affected by atmospheric conditions, other factors and the difference between the altitude of the firer and the target. Direct fire sights may include mechanisms to compensate for some of these.
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Noun
1. fire delivered on a target that is visible to the person aiming it
(hypernym) fire, firing

Fire directed at a target which is visible to the aimer. See also fire. 1/3/73

Tir effectué sur un objectif visible pour le pointeur. Voir aussi tir. 1/3/73