A case of murder with gunshot is reported. A metal bullet is recovered from the body. Primary and Secondary markings on a metal bullet can be used for
Ans is 'a' i.e. Identification of weapon "Primary and secondary marks on the surface of the bullet helps in identification of the gun. Primary marks on the surface of the bullet tells about the 'make' or type of the gun used and the secondary marks which are due to some elevation or depression on the inner surface of the barrel of the gun will tell specifically about the particular gun which has been used when compared with similar markings of a bullet test-fired from the suspected gun. Investigation of Offences on Human Body by Apurba Nandy p48Two types of marks are seen on the surface of the bullet and help in identification of the firearm used.Primary markings (Class characteristics):In all rifled firearms, the bullet is slightly larger than the barrel, and as the bullet passes through the barrel, its sides are marked by the rifling of the barrel. These are k/a primary markings.Primary markings or Class characteristics include- caliber number of lands and grooves {these 2 terms used in describing the rifling found inside the barrel of a firearm. The word lands refers to the raised portion of the rifling, and the grooves refers to the lower portion of the rifling.) direction of the twist of rifling rate of twist of the rifling width of the land and groovesPrimary markings help in identifying the make and model of the firearm used.Secondary markings (individual or accidental characteristics):These markings are caused by irregularities on the inner surface of the barrel which are specific for that particular weapon. These irregularities are produced by the sticking of the particles of the bullet to the bore when shots are fired (this is k/a metallic fouling). Individual characteristics also result accidentally during the manufacturing process.Secondary markings help iii identifying the specific gun from which the bullet was fired.
Identification of weapon
To know the range of firing
Severity of tissue damage
To know time of crime
Misc.