A case of murder with gunshot is repoed. A metal bullet is recovered from the body. Primary and secondary marking on a metal bullet can be used for –
**Core Concept**
The primary and secondary markings on a metal bullet are essential in forensic ballistics for identification and reconstruction of a crime scene. These markings are created when the bullet interacts with the rifling of a gun barrel, resulting in unique patterns that can be used to link a bullet to a specific firearm.
**Why the Correct Answer is Right**
The primary markings on a bullet, also known as rifling marks, are formed by the bullet's passage through the spiral grooves of the gun barrel. These marks are unique to each firearm and can be used to identify the gun used in a crime. The secondary markings, also known as firing pin impressions or ejector marks, are created by the firing pin and ejector of the gun. These marks can also be used to link a bullet to a specific firearm.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because primary and secondary markings on a metal bullet are not used for determining the type of bullet used in a crime.
* **Option B:** This option is incorrect because primary and secondary markings on a metal bullet are not used for determining the velocity of the bullet at the time of firing.
* **Option C:** This option is incorrect because primary and secondary markings on a metal bullet are not used for determining the caliber of the bullet.
**Clinical Pearl / High-Yield Fact**
In forensic ballistics, the primary and secondary markings on a metal bullet are like fingerprints - unique to each firearm and can be used to link a bullet to a specific gun.
**Correct Answer: D.**