10 - 3 Figure 10-1. TRAJECTORY AND MAXIMUM ORDINATE 10-3. CLASSES OF AUTOMATIC WEAPONS FIRE. The U.S. Army classifies automatic weapons fires with respect to ground, target, and weapon. a. Respect to Ground. (See Table 10-3 and Figure 10-2) Table 10-3. CLASSES OF FIRE - RESPECT TO THE GROUND Grazing Fires Automatic w eapons graze f ire w hen t he c enter of t he c one of f ire f ails t o r ise m ore t han 1 m eter aboveground. Grazing fire is employed in the final protective line (FPL) in defense. It is possible only when the terrain is level or uniformly sloping. Any dead space encountered along the FPL must be c overed by indirect fire, such as from an M 203. When firing over level or uniformly sloping terrain, the machine gun M240B and M249 can attain a maximum of 600 meters of grazing fire. The M2 can attain a maximum of 700 meters. Plunging Fires Plunging fire occurs when there is little or no danger space from the muzzle of the weapon to the beaten zone. It occurs when weapons fire at long range, from high to low ground, into abruptly rising ground, or across uneven terrain, resulting in a loss of grazing fire at any point along the trajectory.