Small Arms Know It All :)

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By Haris Amin

Definitions Related to Small Arms
a. Barrel. It is a metallic tube, which can be rifled or smooth.
b. Bore. Inner/ interior portion of the barrel is known as bore.
c. Chamber. It is the rear portion of the barrel, which holds the cart.
d. Rifling. A barrel is said to be rifled when it has spiral grooves cut down the bore, there are lands between the grooves.
e. Caliber. Caliber is the (standard) diameter of the bore excluding depth of the rifling grooves.
f. Twist. Twist of the rifling is the distance, measured in Caliber, in which the grooves make one complete turn / circuit of the bore.
g. Axis of Barrel. This is an imaginary line through the centre of the bore from breech to muzzle.
h. Line of Sight. This is a straight line from the firer's eye through the sights of the rifle.
j. Line of Fire. This is the direction to the target from the muzzle of a weapon.
k. Jump. It is the angle in the vertical plane between the line of departure and the axis of the bore before firing.
Definition Related To Motion Of Projectile
i. Muzzle velocity It is the velocity with which a projectile leaves the muzzle of a weapon. (3 to 4 milli seconds).
j. Line of Departure This is the direction of motion of the projectile as it leaves the muzzle. It is a tangent to the projector of the muzzle.
k. Trajectory It is the curved path taken by a bullet through its flight. The main factors that influence trajectory are:-
(1) The velocity of the Bullet :-Higher the velocity of the bullet greater will be its range.
(2) The gravity of the earth :- Gravity of earthis a constant factor and the earth attracts all objects towards its centre with an acceleration of 9.8 m/sec.
(3) Rotation of the Bullet :-Higher the rotation of the bullet greater will be its stability and greater the range.
(4) Resistance of Air :-Greater the resistance of air lower will be the range of the projectile.
l. Vertex or Culminating Point. This is the highest point above the line of sight that a projectile reaches in its flight to the target. This point occurs at little beyond half the distance, which the bullet travels.
m. Point of First Catch This is the point where a bullets strikes the top of the target.
n. Point of First Graze This is the point where a bullet first strikes the ground.
o. Dangerous Space At a particular range this is the distance between the first catch and the first graze. Dangerous space depends upon the following:-
(1) Range.
(2) The height of the weapon above ground level.
(3) The height of the target.
(4) The flatness of the trajectory of the weapon.
(5) The confirmation of the ground.
p. The Dangerous Space Increase
(1) The nearer the weapon is to the ground.
(2) The taller the objective fired at.
(3) The flatter the trajectory.
(4) The ground sloping with the fall of the trajectory.
(5) The dangerous space decrease, if weapon is placed higher of the ground and ground is not slopping with the fall of bullet. As the range increase owing to the steeper angle of descent of the bullet the dangerous space decrease.
j. Remaining Velocity. This is the velocity of the projectile at any specified point on the trajectory. When it is not specified it refers to the point of graze.
k. Drift. It is the movement of a projectile in a lateral direction of right angles to its principal motion. It is caused by reaction between the air and the spinning projectile.
l. Stability. It is the tendency of a projectile to return to its level or balanced position. Without stability, a projectile would tumble over and will have a very shot range.
Definition Related To Automatics fire
a. Burst of Fire. A number of rounds fired with one squeeze of the trigger of an automatic weapon is termed as a burst of fire.
b. Cone of Fire. When a burst is fired the bullets don't follow the same path. The vibration of the gun, variation in the ammunition and changing conditions of the barrel cause each trajectory to differ slightly from the other in a burst. The group of trajectories formed by a single burst is called the cone of fire.
c. Beaten Zone. The beaten zone is a long elliptical pattern formed by the inter section of the cone of fire with the ground. The pattern of the bullet is the thickest in the middle of the beaten zone. As the range increase the length of the beaten zone decrease and the width increase. This is due to the increased angle of descent of the bullets.
d. Dangerous Zone. It is the area of the beaten zone plus the dangerous space formed by the lowest bullets of the cone.
e. Ballistics. Ballistics, in its general sense, is the science of the motion of projectile.
Miscellaneous Definitions
a. Yaw. It is the angle between the axis of the projectile and the trajectory along which it is flying. A projectile which has a large yaw has a low stability will have a short range and will be generally inaccurate.
b. Hang Fire. It occurs when the time interval between the releasing of the firing mechanism of a fire arm and the projectile from the chamber is longer than customary. It may be due to many causes, chief of which is faulty functioning of the primer or faulty ignition of the propellant.
c. Rear Opturation. It is the locking or sealing off the breech of weapon to prevent the leakage of gases when a cart is fired.
d. Cooking Off.It is the self ignition of a cart inside an over heated chamber of a weapon.
e. Run Away Gun.When an auto weapon keeps on firing against the wishes of the firer, it is termed as run away gun.
Definitions Related to Ammunition
a. Case The case is of solid drawn brass with a groove on rim for extraction. It holds the entire assembly together i.e. the bullet at one end, the primer/percussion cap at the base and the propellant charge inside the case. It is corrosion resistant, thus moisture is not allowed to enter inside the case.
b. Charge. The cart contains a smokeless powder in the form of small perforated grains or sticks (i.e. nitrocellulose, nitroglycerine, or cordite sticks). This has the property that when suitably ignited it burns uniformly and extremely rapidly producing many times its own volume of gases at a high temp and pressure. No outside agent like oxygen is necessary for its burning.
c. Bullet.Normally bullet is pointed and has a lead core inside a copper envelope. It is designed long shape to have more ballistic coefficient (ability) to maintain velocity against the effect of air. Copper jacketing allows it to be easily engraved by the rifling and a bullet is more stable to reduce the skin friction during its flight through the air. The various types of bullets are:-
(1) Ball Bullets. These have soft cores and are used against personal only.
(2) Armour Piercing Bullet. These have hardened steel cores and are fired against, vehicle, weapons and armed targets in general.
(3) Tracer Bullets. These bullets contain a compound usually similar to barium nitrate in their rear portion. This is set on fire when the bullet is fired. The flash or smoke from this burning permits the flight of the bullet to be seen.
(4) Incendiary Bullets. These bullets mainly contain a mixture in a steel container inside the copper envelope that can be set on fire on impact. They are used against targets that will bum readily.
(5) Armour Piercing Incendiary Bullets. These bullets have a steel core and incendiary mixture inside the copper jacketing. They have the capability of piercing through soft vehicles and set them on fire.