Forensic Medicine

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2.  It is the science of motion of projectile.
Or
 The study of various physical forces acting
on the projectile is known as ballistics.
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3.  Internal ballistics.
 External ballistics.
 Terminal ballistics.
 Forensic Medicine.
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4.  The study of various forces acting on the
projectile, when it is moving in side the barrel
of the fire arm weapon.
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5.  The study of various forces acting on the
projectile, when it moves in the air from the
barrel to the time of reaching the target.
 Forces of medium – air resistance, gravity.
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6.  It is the study of the effect of a bullet/shots
on the target till it comes to rest, resulting in
wound formation (wound ballistics).
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7.  It is also known as firearms identification.
 It deals with examination of fired bullets &
cartridge cases and their identification as
have been fired by the particular gun to the
exclusion of all others.
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8.  BASICALLY THE FIRE ARMS ARE CLASSIFIED IN
TO;
SMOOTH BORED FIRE ARMS
. SHOT GUNS.
GROOVED FIRE ARMS.
i) RIFLES.
ii) REVOLVERS
iii) PISTOLS.
 AIR GUNS
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9. 1. SMOOTH BORED FIREARMS:
Breech loading
Muzzle loading
2. Single barrel
Double barrel

10.  According to the muzzle velocity:
 1. low velocity (up to 1200ft/sec.)
 2. Medium velocity ( 1200-2500 ft/sec)
 3. High velocity ( > 2500 ft/sec)

11. RANGE OF SHOTGUN
Usual range 30 – 40 yards
Muzzle velocity – 800 – 1000 ft./sec
Home made gun: muzzle velocity = 500 ft./sec

12. They fire missiles spinning on their long axis. The
inside of the bore is rifled i.e, it is cut longitudinally
with a No. of spiral grooves (usually 4 – 7) which run
parallel to each.

13. TWO TYPES:
1. HIGH VELOCITY RIFLED WEAPONS
Rifle: It is a long barreled weapon with rifled bore and
is fired from shoulder.
Rifle caliber = 0.30
Muzzle velocity = 2500 ft./sec,
Spin = 3000 revolutions/sec
Range = 600 yards.
Rifles may be single shot , semi automatic, automatic.

14. 2. LOW VELOCITY RIFLED WEAPONS:
e.g, Revolver
A hand gun, not over 10 inches, with a rotating
drum or cylinder behind the barrel. This drum
has chambers for loading 5 or more cartridges.
Muzzle Velocity = 600 – 800 ft/sec

15. PISTOL:
It has no cylinder. Cartridge is loaded into the
Chamber directly. It may be single shot, repeating
(having magazine), semi automatic, self-loading.
Range: 100 yards
Muzzle Velocity: 1200 ft/sec

16. AIR PISTOLS + AIR GUNS:
They release pellets; which are
propelled by air compressed in a cylinder.
Used for killing rats, birds etc.
Range: 30 yards
Muzzle Velocity: 400 – 700 ft. sec
Some may give fatal injuries to human
beings.

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20. Important terms of firearms
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21.  It is any instrument or device that propels a
projectile by the expansive force of the gases
generated by combustion of an explosive
substance.
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22.  1.BARREL.
 2.FIRING PIN.
 3.HAMMER.
 4.TRIGGER.
 5.BUTT.
 6.MAGAZINE.
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23.  It consists of a cylindrical steel tube, which is closed
at its proximal end known as BREECH END
 DISTLE END which is always open known as MUZZLE
END.
 Breech end contains a chamber for accommodating
cartridge and may carry an extractor to remove the
cartridge case after firing.
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24.  A firing pin is present incorporated with
hammer and on loading, it is held in cocked
position on pulling the trigger it hits the
sensitive primer at the base of cartridge and
firing occurs.
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25.  In most of the guns a hammer is present
which on loading the weapon is held in
cocked position and on pressing the
trigger, hammer strikes the primer leading
to fire (if hammerless than firing pin strikes
).
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26.  It is a lever situated in front of butt or hand
grip.
 As the weapon is cocked and trigger is
pressed it releases firing pin or hammer
resulting in the detonation of the primer in
the percussion cap of a cartridge.
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27.  Is part of fire arm gripped in hand in small
barreled fire arms such as pistols, revolvers
etc.
 While the butt is long and shaped to fit the
shoulder in cases of shot gun and rifles.
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28.  It is a spring loaded box or container carrying a
number of cartridges. It may be separated or attached.
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29.  Means the diameter of the interior
of the barrel of a firearm and is
expressed in inches or in
millimeters.

30.  Projectile: Any article being capable of projecting
with great force from a fire arm weapon is known
as projectile such as pellets in shot guns and bullet
in rifled fire arms.
 Bullet: means the projectile of a rifled firearm.
 Cartridge: means one unit ammunition.
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31.  Technically means the diameter of the
inside of the bore(land to land) in 1/100th
of an inch.
 Thus caliber 22 means 22/100 inch =
0.22inches.
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32.  Means a small metal cap, at the
base of the cartridge, holding a
sensitive mixture that is
detonated by a blow either from
a hammer or firing pin.
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33.  Means the deviation between the long axis of
the bullet and the axis of the path of the
bullet.
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34.  Velocity: it means speed of the projectile in
feet per second or meters per second.
 MUZZLE VELOCITY:
The maximum velocity of the projectile when
it comes out of the muzzle of firearm is
known as muzzle velocity.
1. Shot Guns. 1000 feet/ sec.
2. Rifles. 2000-3000 feet/Sec.
3. Pistols. 1200 feet/Sec.
4. Revolvers. 600 feet/Sec.
5. Air Rifles, and Air pistols 400-700
feet/Sec.
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35.  Range: It means the distance that the
projectile travelled from the muzzle to the
target. Generally, range of a firearm denotes
the maximum distance upto which it can
accurately hit the target.
 a. EFFECTIVE RANGE:
It is that range in which the firearms can
cause maximum damage.
b. HITTING RANGE
It is that range up to which the projectile can
reach the target, but will cause minimum
damage.
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36. FIRE ARM EFFECTIVE
RANGE
HITTING
RANGE
SHOT GUN 30-40 YDS 100-200 YDS
RIFLES 1000-1500YDS 2000-3000YDS
PISTOLS &
REVOLVERS
200 YDS 700-800 YDS

37.  The internal lumen
of the barrel is
smooth in smooth
bored fire arms
such as shot gun,
 while it contains
spiral grooves
running parallel to
each other and are
seen in Rifles,
Revolvers, Pistols.
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38.  The function of grooves is to impart a spin
movement to the bullet while passing
through the barrel.
 Advantages of Rifling:
 1. it gives spinning movement to bullet.
 2. Prevents from wobbling.
(stabilizes the bullet).
 3. Increases the power of penetration.
 4. Gives greater accuracy and longer range.
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39.  Choking: It means the degree of constriction
at the end of the shot gun bore, provided for
keeping the shot spread more compact.
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40.  It increases hitting range
 Decreases the spread of pellets
 Increases the velocity of shot.

41.  FULL CHOCK:
constriction is 1mm
 HALF CHOCK:
constriction is 0.50mm
 QUARTER CHOCKED:
constriction is 0.25mm
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42.  Smooth, true cylinder weapon in which
there is no constriction in the barrel
and the size is same i.e, smooth from
breech end to muzzle end.

43.  In case of 12 bore shot gun, we take 1 lb of
lead and make 12 rounded balls of equal
weight and each ball fits exactly the internal
diameter of the barrel.
 So as the bore increases the internal diameter
of the barrel decreases.
 Note: Size of lead shots has nothing to do
with the bore No.
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44.  In grooved fire arms if we take transverse
section of barrel, there are depressed areas
alternating with raised areas known as
LANDS.
 Caliber indicates land to land width of the
barrel.
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