LEARNING OBJECTIVE: Describe general prefire requirements for naval gun mounts.

Before firing, each of these systems must be inspected and tested. Gun power drives and the loading

Figure 6-12.-Firing cutout mechanism, response gearing, and cam.

system have their hydraulic fluid levels checked, are inspected for gear adrift, and then are test-operated. Fluid levels in the recoil and counterrecoil systems are checked and firing circuits and firing cutouts are tested. The detailed procedure for performing prefire checks is provided on the appropriate system maintenance requirement card (MRC). Prefire and postfire barrel maintenance requirements are described in chapter 12.

The components we have just described are common to all guns. We will now discuss the individual gun systems in the fleet today, paying particular attention to the loading system in each one.

GUN SYSTEMS

LEARNING OBJECTIVE: Discuss the gun crew positions and their responsibilities. Describe the loading sequence of the Mk 45 and Mk 75 gun mounts.

As you read this section and study the illustrations, note the different configurations of machinery designed to accomplish the same task from one gun to the next.

Figure 6-13.-The 5"/54 Mk 45 Mod 0; general arrangement.

When speaking of gun equipment, all directional nomenclature (left, right, front, back) is relative to the muzzle of the gun (the end of the barrel that the projectile exits when fired) that is to the front as you stand inside the gunhouse.