Firing Marks

Marks produced during firing mechanism

1. Marks produced during firing By :- P ooja dixit Submitted to :- Ketan Sir

2. Gun It has following main parts :-

3. Marks produced while firing

4. Firing marks 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. Firing marks on bullet 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. Firing marks on cartridge 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. Breech face mark 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 .

11. Breech face mark

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

14. Chamber marks 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.

16. Thank you