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CHAPTER 2
NAVAL GUNS
Most naval ships and aircraft are fitted
with various kinds of guns.
Guns may be used against surface,
shore, and air targets.
Ship guns designed for engaging
both air and surface targets
Dual-Purpose Systems
In automatic, gun recoil ejects the
fired powder case and reloads the
gun.
A weapon consisting of a metal tube
or barrel closed at one end, with
mechanical attachments from which
projectiles are shot by the force of an
explosive.
Gun
Gun Components
Gun Components
The loading cycle for a large baval breech loader. Notice that there is a
Series of interlocking doors that never permit an open path from the
Gunhouse, down, which a flash might travel to the magazine.
Gun Barrel Rifling
Spiral grooves cut in the inner
surface of the gun barrel to give
the projectile a rotating motion
and thus a more precise trajectory
Rifled Barrel
The system of rifling spiral
grooves cut inside the bore
Rifling Lands
Rifling causes the projectile to spin in
flight, which keeps the projectile from
tumbling after it leaves the barrel, thus
providing greater accuracy.
BARREL
Rifling
Gun Measurement
The diameter of the bore of a gun
taken as a unit of measurement
Caliber
Gun Measurement for Barrels
over 3" in Diameter
Caliber = barrel length ÷ bore
diameter in inches.
A 20-millimeter machine gun has a bore
diameter of 20 millimeters. A .32-caliber
revolver has a bore diameter of .32 inches.
20–millimeter .32–caliber
A gun having a bore diameter of 5 inches and
a barrel 190 inches long is designated 5-inch,
38-caliber (written 5/38).
What is the designation of a gun
having a bore diameter of 5 inches
and a barrel 270 inches in length?
What is the designation of a gun
having a bore diameter of 5 inches
and a barrel 270 inches in length?
It is called a 5-inch, 54-caliber gun
(5/54).
Gun Elevation
The total vertical arc through which a
gun barrel can be raised and lowered
Arc of Elevation
Gun Train
The total horizontal arc through which
a gun mount may be rotated
Arc of Train
Cutout cams prevent guns from being fired
into the ship’s or aircraft’s structure.
The entire structure between
the gun and ship’s structure
Gun Mount
Battery
A group of gun
mounts of the
same size, normally
controlled from the
same point
Consists of the largest size gun
on board a ship
Main Battery
Consists of dual-purpose guns,
or guns of the next smaller size
Secondary Battery
Effective range depends
on:
• Initial velocity
• Weight of projectile
• Caliber of the gun
• Fire control system
5" Projectile
Projectile range on larger caliber gun
projectiles can be extended by rocket
assistance.
5" Rocket Assisted Projectile
They are designed to extend the
range of the projectiles and are
filled with high explosive (HE)
material.
Rocket-Assisted Projectiles (RAP)
Less than 8 inches
and larger than 4
inches
Less than 4 inches
in diameter
5"/54 Caliber Gun Mount MK 45
5"/54 Caliber Gun Mount MK 45
Firing rate — 40 rounds per minute
Maximum Range — 24,500 yards
(23,700 meters)
5-inch Projectile
Weight – 72 pounds
Oto Melara 76mm/62–Caliber
MK 75 Gun Mount
Oto Melara 76mm/62–Caliber MK 75
Gun Mount
Firing rate — 80 – 85 rounds per minute
Maximum Range — 17,800 yards
(19,200 meters)
Phalanx Close–in
Weapons System
(CWIS) 20mm Gun
System
A last-ditch
weapon against
an antiship
cruise missile
Search Radar
Tracking Radar
6 – 20mm
gun
barrels
Ammunition
drum – 900+
rounds
The six-barrel
Vulcan Gatling
gun can fire
3,000 rounds
per minute.
The gun is
computer
controlled.
Gun Ammunition — Principal
Components:
Propelling charge
Projectile
An object fired from a gun with an
explosive propelling charge, such
as a bullet, shell, rocket, or grenade
Projectile
Bag Ammunition
Case Ammunition
DER
Semifixed Ammunition
Fixed Ammunition
Refers to a round that consists of a
projectile and a separate case charge
loaded one after the other
Semifixed Ammunition
Refers to a round in which the projectile
and powder case are permanently
attached (standard in 3‖ and smaller guns)
Fixed Ammunition
Propellant Components
PRIMER
IGNITERMAIN CHARGE
PRIMER
IGNITERMAIN CHARGE
Propellants are chemical compounds
that burn at a rapid rate rather than
detonate or explode.
PRIMER
IGNITERMAIN CHARGE
The first stage in a propellant train is called a
primer; it produces a hot flame that sets off
the next stage, called igniter; the igniter sets
off the main charge.
primer
igniter
main charge
The three main parts
of a projectile are:
• Its metallic body
• The fuze that sets
off the main charge
• The explosive
burster charge
Gun Projectile Assembly
Body
Explosive
Charge
ADF
(Auxiliary
Detonating
Fuze)Nose Fuze
Projectile Characteristics
ROTATING
BANDBODY OGIVE
BASE BOURRELET NOSE
The curved nose of a missile or rocket
Ogive
The widest part of the projectile, located
immediately to the rear of the ogive
Bourrelet
Three classes of projectiles:
• Penetrating
• Fragmenting
• Special purpose
Penetrating projectiles are
designed to penetrate the
target before exploding.
Armor-Piercing (AP) Projectile
Fragmenting projectiles are designed
to damage by blast effect and
fragmentation.
These projectiles have relatively thin
walls and large burster charges
A bomb designed to break into many
small, high-velocity shrapnel fragments
when detonated
Fragmentation Bomb
Shell fragments
Shrapnel
Antiaircraft Common (AAC) Projectile
Antiaircraft projectiles are normally fuzed to
detonate in proximity of aircraft with the
fragments penetrating the aircraft skin
BASE DETONATING FUZE
AUXILIARY DETONATING FUZE
MECHANICAL TIME FUZE
High Explosive–Point Detonating
(HE–PD) Projectile
High Explosive–Point Detonating
(HE–PD) Projectiles
These are used against lightly armored
surface targets such as torpedo boats,
shore installations, or personnel.
Special purpose projectiles have
a variety of applications, including
illumination, smoke, chaff, and
target practice, and are not intended
to inflict damage by blast or
fragmentation.
Illuminating (ILLUM) Projectile
PARACHUTE
Illuminating
Projectiles
Often called star
shells, they contain
a bright flare
attached to a
parachute. The
flare is intended
to illuminate an
enemy target or
terrain as it slowly
descends under
the parachute.
Parachute
White Phosphorous (WP) Projectile
A smokeless powder consisting of
nitroglycerine and cellulose nitrate
chiefly in a 40 to 60 percent ratio;
used as a solid fuel for rockets
Ballistite
Chaff Projectile
Strips of metal foil dropped by an
aircraft to confuse enemy radar by
creating false blips
Chaff
Nonfragmenting Projectiles
Produce bursts of various colored smoke
for antiaircraft gunnery practice
Target projectiles contain sand or
other inert material to simulate the
weight and balance of burster
charges; they are used for surface
gunnery practice.
Fuze
A device that detonates the
burster charge
A mechanical or electronic device to
detonate an explosive charge,
especially as contained in an artillery
shell, a missile, projectile, or the like
Fuze
A tube, cord, or the like, filled or
saturated with combustible matter,
for igniting an explosive
Fuse (different spelling)
Fuzes are classified by their function
as:
• Impact
• Time
• Proximity
Fuze
Controlled Proximity (VT) Fuze
A design for detonating a charge, as
in a projectile, within a predesignated
radius of a target
Proximity Fuze
Controlled Variable–Time Fuze (CVT)
Delays projectile arming for a set
time after it is fired
Firing over a Friendly Ship
Note: Impact Backup in VT Mode
Air
Burst
Impact
Burst
Enemy
Mechanical Time Fuze
It contains a clock mechanism that
explodes the projectile after a preset
amount of time elapses.
Antiaircraft guns put up a ―flak‖
screen to protect carrier task forces.
Flak
A heavy antiaircraft barrage through
which aircraft must fly to attack their
target
Artillery projectiles have been produced that
can dispense chemical or biological agents,
and have been used in some of the conflicts
in the Middle East.
Iraqi Chemical Artillery Projectiles
Naval Gunfire Support
Shore bombardment was
common in World War II.
Naval gunfire support for amphibious
operations must be:
• Carefully planned
• Executed with precision
Support roles for naval gunfire include:
• Mine warfare activities
USS Defender
(MCM 2)
• Sea/Air rescue missions
• Reconnaissance and demolition
operations
• Feints
• Raids
• Flak suppression
during air strikes
• In interdiction of coastal
roads, railroads, airfields,
and troop assembly areas
Steady bombardment of enemy positions
and communications lines for the
purpose of delaying and disorganizing
progress
Interdiction
THE END