Under what condition does grazing fire become ineffective?

Grazing fire is most effective when it is employed against targets that are close to the ground, typically up to 600 meters. This type of fire allows the bullets to travel just above the ground, preventing them from arching and potentially impacting the ground before reaching the target.

In elevated target situations, grazing fire can become ineffective because the angle of elevation changes the trajectory of the rounds. When targets are situated at a higher elevation than the firer, the rounds may arc upwards instead of maintaining the low trajectory that grazing fire relies upon. This trajectory shift can cause the rounds to miss the intended targets or possibly hit above them, reducing the overall effectiveness of the fire.

Therefore, in scenarios where the target is elevated relative to the firer, the intended impact of grazing fire is compromised, making this condition critical to understand for proper machine gun employment.