Cartridges Design The bullet, usually made of metal, is out front with the cartridge, holding the primer and propellant powders, behind. Change Your Life *

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What Are The Three Types of Bullets? Change Your Life *

How a Gun Works 1. The firing pin hits the base of the cartridge, igniting the primer powder. 2. The primer powder sparks through the flash hole to the main propellant supply. 3. The pressure of the explosion pushes the bullet from the case into the barrel. 4. The bullet follows the lands and grooves spiraling out of the barrel. ● Change Your Life *

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What is effect does rifling do to a bullet? Rifling is the process of making spiral grooves on the inside of a rifle barrel which stabilizes the projectile and improves aerodynamic stability and accuracy. Change Your Life *

A BROACH CUTTER USED TO CREATE RIFLING IMPRESSIONS IN A BARREL Change Your Life *

As a result of rifling, a barrel will impress a negative impression of itself on the sides of the bullet Change Your Life *

Matching impressions Change Your Life *

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A Fired bullet: Class evidence Different gun manufacturers use different rifling techniques. These techniques impart the class characteristics on a fired bullet. Number of impressions Width of impressions Depth of impressions Angle of impressions Change Your Life *

Q: How are these 2 guns different A: caliber Change Your Life *

What is caliber? Caliber = the diameter of the bullet. Measured in hundredths of an inches..22,.357, or.50 Measured in metrics 9mm Question: Why should the caliber of ammunition match the firearm that shoots it? If they do not match, what could go wrong? Change Your Life *

Showing variation within caliber Change Your Life *

Striations on bullets are not the only features used in firearm investigations. BREECH MARKS PLAY A VITAL ROLE IN DETERMINING IF A CERTAIN BULLET WAS FIRED FROM A FIREARM. BREECH MARKS ARE FOUND ON THE REAR OF A FIRED CARTRIDGE Change Your Life *

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When a bullet is fired, the explosion forces: 1.the bullet down barrel 2.the cartridge back against breech –Leaving a negative impression on the back of the cartridge Change Your Life *

Depending on the make of gun & normal wear and tear, the breech markings will pick up class, and hopefully, individual characteristics. Change Your Life *

Examples of breech markings Change Your Life *

Shot Gun vs. Handgun Shotguns have smooth barrels with no rifling. Are there lands or groves on the bullet(s)? How can a F.S. identify trace evidence left by a shotgun? Only by marks on the spent shell casing(s): Change Your Life *

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Shotgun into ballistics gel Change Your Life *

How CSI determines if a recovered bullet from a crime scene came from a suspected gun Disclaimer: this video is oooooold Change Your Life *

THE END Change Your Life *