had a firing rate of 10 to 12 rounds a minute. See also the 8"/55 caliber Mark 71 gun. Projectile The Projectile (pictured) has three major parts: the body, the fuze, and the explosive charge. Projectile body The body is basically a machined steel tube with an ogive shape at one end. At the ogive and rear ends are threaded openings used to the install the shell's filler and hold the fuzes. Around the tube near the base is a copper alloy ring called the Rotating Band. This band has a diameter larger than the bore, and when the projectile and powder case are rammed into the chamber, the band is jammed into the grooves of the bore's rifling. It forms a gas seal between the projectile and the bore. Also, as the projectile travels down the barrel, the band grips the rifling to impart spin to the projectile. Fuze The Fuse detonates the projectile to cause maximum damage to the target. Different targets required different fuzes. The safety requirements of a fuze are that... ... it is safe to handle. (i.e.: It will not arm if dropped, rolled, or shaken.) ... it remains unarmed in the bore, and until the projectile is well clear of the firing ship to protect exposed personnel. Therefore, when the gun is fired, the following events take place: 14,000g acceleration from the burning propellant in the bore. This acceleration is used to setback (i.e.: Force to the rear.) some fuze parts from unarmed to armed positions due to their inertia. Centrifugal force from the 12,360 rpm projectile rotation. This force causes other parts to move outward. 7.2g deceleration from aerodynamic drag after the projectile leaves the muzzle. Due to inertia, other movable parts will creep forward. All of these events must take place in the correct order to arm the fuze. List of fuze types: Mechanical time fuze A nose time fuze that detonates the shell after an adjustable time interval has elapsed since firing. Base detonating fuze A base impact fuze screwed into the rear of a projectile to protect the fuze during impact. It delays the shell's detonation about 25 ms after impact, allowing the projectile to penetrate the target prior to detonation. Point detonating fuze A nose impact fuze. Very fast detonation on the surface of the target. VT fuze The VT (Variable Time, this is a counter-espionage decoy designation) fuze