In the drop-fire method (conventional mode), as soon as the gunner ensures that the mortar is laid correctly, he removes the sight unit and sets the selector to the D (drop) position. This is done only for the first three rounds or until the baseplate is settled, at which time the sight may stay on the mortar while firing. The gunner kneels on the left side of the cannon and looks into the sight unit. The assistant gunner kneels on the right side in front of the traversing mechanism, facing rearward. The ammunition handler kneels beside the assistant gunner slightly to the rear (fig. 14-18).

The ammunition handler adjusts the propellant charge for the desired range, sets the fuze for the desired

Figure 14-19.-Firing position: Hand-held mode.

burst effect, removes the safety wire/pin, and hands it to the assistant gunner. As the example fire command stated earlier, the method of fire is ONE ROUND AT MY COMMAND; the gunner cannot fire until given the command. When the gun is ready to fire, the gunner notifies the FDC or squad leader that the gun is UP. The gunner then kneels in an upright position. The next command that the gunner receives is HALF LOAD. As the gunner repeats the command, the assistant gunner grasps the body of the round with two hands near the center of the round. He inserts it, fuze end up, into the muzzle beyond the narrow part of the body.

CAUTION

If a crew member is within one meter of the muzzle during firing, hearing protection must be used.

At the command FIRE, the assistant gunner releases the round, passes his hands partly down the outside surface of the barrel while pivoting to his left and bending toward the ammunition handler. When the firing selector is set at the T (trigger) position, the gunner squeezes the trigger after the round hits bottom on the command to FIRE.

The hand-held mode (fig. 14-19) requires no sight unit. The range indicator assembly is used to estimate target range. Use of the range indicator is for M720/M888 cartridges only. As the gunner kneels directly behind the barrel, he places a glove on his left hand to hold the barrel. Next, he puts his right hand on the trigger/handle and points the mortar toward the target. At this time, the gunner reads the range indicator.

Figure 14-20.-Range indication.

The range indicator (fig. 14-20) consists of a vial that contains a ball that moves when the cannon is elevated or depressed to indicate the firing range. The black scale is for charge one; the red scale is for charge zero. The yellow index (range 3 on the red scale and range 10 on the black scale) is a warning reminder to brace the baseplate before firing.

The ammunition handler prepares the cartridge. As the gunner sets the firing selector in the T (trigger) position, the assistant gunner inserts the round into the muzzle, releases the round, and assumes a safe position. The gunner lays-in the weapon by using the range indicator and sighting over or on the side of the muzzle for the azimuth. Holding the mortar steady, the gunner assumes a safe firing position. When the weapon is on target, the gunner squeezes the trigger to fire, then releases the trigger in preparation for the next round.