Marks produced during firing mechanism

1. By :- Pooja dixit
Submitted to :- Ketan Sir

2. • It has following main parts :-

3. Firing
marks
Cartridge
case
Firing pin
mark
Breech
face mark
Extractor
mark
Ejector
marks
Chamber
marks
Bullet
Riffling
patterns
Wear and
tear marks

4. • The marks generated or developed while firing a
projectile through a gun .
• Basically shots , doesn’t gets any sort of firing marks over
it .
• Whereas bullets and cartridges sustain the firing marks
over them .

5. • Only the outer covering of the bullet is the only location
where any type of firing marks are found .
• No marks are found on the base of the bullet .

6. • The outer covering of the bullet gets riffling marks while
firing process .
• This marks are individual traits when it comes to
individualise a gun .
• This patterns may be clockwise or anticlockwise .

7. • The cartridge case constitutes of following 5 types of
firing marks :-
1 . FIRING PIN MARK :-
Firing pin impressions are indentations created
when the firing pin of a firearm strikes the primer of
center fire cartridge case or the rim of a rim fire
cartridge case.

8. • If the nose of the firing pin has manufacturing
imperfections or damage, these potentially unique
characteristics can be impressed into the metal of the
primer or rim of the cartridge case.

9. • Very high pressures are generated within a firearm when
a cartridge is discharged.
• These pressures force the bullet from the cartridge case
and down the barrel at very high velocities.
• When a firearm is discharged, the shooter will feel the
firearm jump rearward.
• This rearward movement of the firearm is
called recoil. Recoil is for the most part caused by the
cartridge case moving rearward as an opposite reaction
to the pressures generated to force the bullet down the
barrel.
• When the head or base of the cartridge case moves
rearward, it strikes what is called the breech face of the
firearm

10. • The breech face rests against the head of the cartridge
case and holds the cartridge case in the chamber of the
firearm. When the head of a cartridge case slams
against the breech face, the negative impression of any
imperfections in the breech face are stamped into either
the primer of the cartridge case or the cartridge case
itself.
• It can be parallel and circular . Also it may not contain
any definite shape .

12. • Ejector marks are sometimes created when cartridges or
cartridge cases are ejected from the action of a firearm.
• Ejector marks can be either striated or impressed but the
impressed ejector marks not only can be used to identify
a cartridge case as having passed through a firearm's
action they can also be an indication that the cartridge
case was fired in the firearm.

13. • These marks are mostly found at the extracting groove
of the fired cartridge case.
• They are Cause by its withdrawal from the chamber.

14. • These marks are mostly found around the body of the
fired cartridge case cause by the irregularities of nips
inside the walls of the chamber.
•

15. • Also the firing pin mark , ejector mark and extractor mark
are specifically indentation marks .
• Whereas chamber marks and breech face marks are the
combination of striations and indentation marks.