7. SHOTGUN CARTRIDGE
BASE IT CONSISTS OF A
METAL CYLINDER (brass)
WHICH IS CONTINUOUS
WITH A CARDBOARD OR
PLASTIC CYLINDER
THE CASE IS RIMMED
WHICH KEEPS THE CARTRIGE
CORRECTLY IN THE
CHAMBER AND FACILITATES
EXTRACTION.
8. FILLING OF CARTRIDGE FROM
BASE ARE :-
1. PERCUSSION CAP
2. GUN POWDER
3. FELT WAD WITH CARDBOARD
DISC
4. THE SHOT
5. RETAINING CARDBOARD DISC
11. THE DIAMETER OF WADDING
USED IN THE CARTRIDGE IS
GREATER THAN THAT OF THE
BORE OF THE GUN.
WAD ACTS AS THE PISTON AND
SEALS THE BORE COMPLETELY
THUS PREVENTING THE
EXPANDING GASES FROM
ESCAPING AND DISTURBING THE
SHOT CHARGE.
WADS
12. THE WAD CONTAINS GREASE
WHICH LUBRICATES THE BORE
AFTER FIRING OF EACH ROUND
THE GUN POWDER IS PROTECTED
FROM GREASE BY THIN GREASE
PROOF CARD WAD
WADS
13. THE SHOT CONSISTS OF SEVERAL
HUNDRED SMALL LEAD SHOTS .
NUMBER DEPENDS ON :-
•THE SIZE OF THE LOAD
•SIZE OF THE INDIVIDUAL PELLET
SHOT
22. BLACK POWDER
•IT IS DESIGNATED AS FG,FFG,FFFG
•THE MORE NUMBER OF F’s , THE
FINER ARE THE GRAINS AND THE
FASTER THEY BURN
•IT BURNS WITH PRODUCTION OF
HEAT ,FLAME AND SMOKE
•1 GRAM OF POWDER PRODUCES
3000 TO 4500 CC OF GAS
23. SMOKELESS POWDER
•THEY PRODUCE MUCH LESS SMOKE AND
FLAME AND ARE MORE COMPLETELY
BURNT THAN BLACK POWDER
• 1 GRAM PRODUCES 12000 TO 13000 CC
OF GASES
•THE COLOUR VARIES FROM BRIGHT
ORANGE TO BLUISH BLACK
24.
25. BULLETS
THE TRADITIONAL BULLET IS MADE OF SOFT METAL AND HAS
A ROUNDED NOSE .
THE METAL USED IS LEAD
THE MISSILE IS THE COMMON BULLET USED IN PISTOLS AND
RIFLES.
IN PISTOL THE BULLET IS SHORT AND THE POINT IS ROUNDED
IN RIFLES THE BULLET IS ELONGATED AND POINTED
27. FULL METAL JACKET BULLET
•COVERING IS MADE WITH TOUGH AND HEAVY JACKET
COVERS
•BASE HAS SOFT METAL INTERIOR
•THE TOUGH METAL MAY BE MADE OF
STEEL,ZINC,COPPER,NICKEL
28. SEMI-JACKETED BULLET
•IT HAS A TOUGH JACKET BUT THINNER COMPARED TO FULL
METAL JACKET BULLET
•THE NOSE IS FULLY OR PARTLY EXPOSED
29. A DUMDUM BULLET IS ONE WHICH FRAGMENTS EXTENSIVELY
UPON STRIKING
33. MECHANISM OF DISCHARGE OF PROJECTILE
TRIGGER IS PULLED
FIRING PIN STRIKES THE PRIMER CAP
THE PRIMING EXPLODES
SENDS FLASH TO THE POWDER FILLED CASE
POWDER CHARGE BURNS
LARGE AMT OF GAS PRODUCED INCREASES
PRESSURE
36. 1- Loss of substance
This loss depends on the size of missile, velocity and distance of firing.
2- Presence of two wounds inlet and exit
(grazing of the bullet)
3- Possible presence of associated of projectile
(Powder marks)
4- Beveling occurs in flat bones .
37.
38. DIFFERENCE BETWEEN INLET & EXIT
exitinlet
LargeSmall Size
LessMore Loss of
substance
NO++++ Powder
marks
EvertedInverted Edge
EternalInternal Beveling
39. Factor affecting the shape of the FA wound
1- The type of the weapon
2- Distance of firing
3- Direction of firing.
4- Site of the wound
5- Type and amount of the powder
40. Estimation of the distance of firing:
1- In cases of short distance (near firing):
Powder marks
II- In cases of long distance (far firing):
• The estimation of distance is based on the extent
of dispersion of shots
• In cases of bullets it is estimated by the amount of
penetration
41. point blank firing (0-15)
• The inlet is cross shaped
• Everted
• Burnt (flam).
• Blackening (smoke)
• Tattooing (unburned particles).
42.
43. In contact firing
• Burning take the shape of the muzzle,
• Minimal blackening and tattooing.
Why
44.
45.
46. Medico legal importance of powder marks:
1- Diagnosis of fire arm injuries
2- Differentiation between inlet and exit
3- Identification the type of powder used
4- Estimation the distance of firing
5- Determination the direction of firing
47. Identification of the weapon used
• Finger prints
• Smell of burnt powder
• Type and bore compared with projectile
extracted form the victim
• Experimental examination of the suspected
weapon
• Empty cartridge at the scene of the crime
48. Suicide , homicide or accidental
1. Circumstantial evidence
2. Scene of the crime
3. Examination of the victim
• Sex - Victims clothes - Cadaveric spasm
• Blackening of the victim's fingers
• Signs of resistance
49. 4- Examination of the wound
• Site of the wound
• Number of wounds
• Distance of firing
5 -Examination of the weapon
• presence of the weapon
• Type of weapon Short – long
6- Examination of the suspected assailant
50. Entrance Wounds
1. Shotguns:
- The mass of shot leaves the weapon initially as a
solid mass, which progressively diverges from
the weapon.
Contact Wounds (touching the skin)
- When a weapon is fired, the bullet, hot gases
from exploding gun powder & metal fragments
from the bullet & the gun barrel are propelled out
of the muzzle at the same time.
- The hot gases & metal fragments are blasted into
the body at the same time as bullet.
51. Contact Wounds cont.
- Round or oval central defect with an „abrasion collar‟
(where the bullet has abraded the skin surface as it
passes through it). The size of the defect is comparable
to the size of the muzzle opening or bore of the
weapon.
- “Pink/red” staining of the skin (due to carbon
monoxide laden gases producing carboxyhaemoglobin)
- Gun powder blackening of the wound edges &
surrounding skin (from soot & unburned propellant
gases).
-Circular bruise over the skin due to muzzle impact.
52. Contact Wounds cont.
Summery
-Wounds are circular
-There may be muzzle mark
-There may be a slight local burning to the skin & hair
-Redness from CO gases
54. Near Discharge
- Within few cm of surface
-Large central defect with „stippling‟ or „tattooing‟
( small, dry, reddish abrasions caused by unburned
powder & small metal fragments striking the skin)
- Smoke soiling
- Lack of muzzle mark
tattooing
Intermediate Range
55. Intermediate Range
-Within 20 cm to 1 m.
- Diminishing of the smoke soiling but powder
tattooing persist
- Burning will be present
- The rim of the wound is irregular forming what is
called „rat-hole‟.
57. Long Range (2-3m)
-Satellite pellet holes will be seen around the
central wound, which diminishes in size as the
range increases.
- the spread of shot in centimeters equal two to
three times the range in meters.
e.g. if the wound pattern is 20 cm across the
discharge was roughly 7 – 10 m so couldn‟t be a
suicide.
58. Long Range ( 20 – 30 m)
-Abrasion collar
-No smoke soiling, burning or powder tattooing.
-Tissue displacement.
-Rarely fatal.
59. Differences between shotgun &
rifles in entrance wound
Rifled weapons:
- show increased amount of tissue destruction due to the
high velocities involved.
-Usually have an entrance and exit wound unless bullet
has struck a bony area such as the skull.
-Estimation of firing range is more difficult than with
shotgun weapons, but in general , contact wounds show
similar features of powder
stippling, blackening, burning, tissue disruption, &
carboxyhaemoglobin formation.
60. Exit wound
-Shotguns: Rarely produce exit wound because they
traverse the body, but if happened it may cause a
huge ragged aperture wound.
-Rifled weapons:
--Exit wound is usually everted with split flaps.
--No burning, smoke or powder soiling.
--if the bullet flattened or has destruct some bone
internally, exit wound may be more irregular and
sometimes very large in size.
63. Accident, Suicide, or
Murder
-Suicides must show wounds which range within the
arms reach unless some devices is present to reach the
trigger.
-Suicides shoot themselves in sites of election which
include the mouth, the front of the neck, the forehead,
or the front of the chest.
-Discharge into the entrance wound are usually on the
side of the dominant hand, but this is not absolute.
-People almost never shot themselves in the eye or
abdomen & naturally not in inaccessible sites such as
the back.
-Women rarely commit suicide with guns & rarely
involved in firearm accidents.
64. Accident, Suicide, or
Murder
-„A shot woman is a murdered woman until proved
otherwise‟.
-Multiple firearm wounds suggest homicide, but this is
by no means inevitable.
-It‟s unwise to state that a gunshot wound must have
been immediately fatal, unless destruction of brain
stem or heart or transection of the aorta has occurred.
-There are many instances of gross brain
damage, especially in the cerebrum, bring followed by
prolonged purposeful activity.
-In suicide weapon must be present, though it may be
at a distance from the body.
65. Doctors duty in firearm
injuries & deaths
-Any missile, foreign body such as wads and any
skin removed from the margin of a repaired
firearm wound should be carefully preserved for
the police.
-The skin in post-mortem examination around
the entrance wound should be removed & kept
without formalin, but refrigerated if
necessary, for forensic tests for powder residue.
-In many countries firearm injuries must be
reported to the police even if not fatal.
