2 Firearms Identification A discipline mainly concerned with determining whether a ______ or ________ was fired by a particular _______.
3 BarrelA)B)Bullet__________ impression_____________ impressionRifling - the __________________Grooves that are formed in the boreOf a firearm barrel. Makes projectiles______________ when fired
4 ______ cutter used to create _______ impressions in a barrel A -_______ -the diameter ofThe bore of a rifled firearm.The caliber is usally expressed in hundreths of an inch or millimeters. Example 22 _____Or 9 ______.
6 Bullet Comparison Class Characteristics Different gun manufacturers use different rifling techniques. These techniques impart the class characteristics of a bullet.---- _____________of lands and grooves-- _____________ of lands and grooves
7 Bullet Individual Characteristics •A cross section of a gun barrel will show smallgrooves or striations all along lands and grooves( )•These are created when the barrel is rifled. No _____ gun barrels have the exact same markings.•These markings leave _______Striations or impressions on abullet. This allows a bullet to betraced back to a _______firearm.
8 Bullet Individual Characteristics It is possible to determine the bullet on the ____ and the bullet on the ______ are from the same gun by matching the _____________. See examples A and B
12 When a cartridge is fired, the explosion forces the bullet down the barrel and the shell casing is forced back against the _______. This leaves impressions unique to the individual gun’s _______ on the shell casing.
14 Firing Pin Marks In order to fire the cartridge, ________ must first be ignited. To accomplish this a ______ ____ strikes the center ring of the cartridge. This will in turn leave a _______ impression that is unique to the ________ of that particular gun.
16 and ejector throw the spent shell casing from the chamber of the gun. Extracting Pin and Ejector MarksThe extracting pinand ejector throw the spent shell casing from the chamber of the gun.These leave marks on the shell casing that are unique to those parts on that particular firearm.
17 Shotgun identification Shotguns have ________ barrels with not rifling. Therefore there are no land or groove marks left on the bullet. Identification can still be made by comparison of ________________ markings on shotgun shell.
18 REVIEW Define the term “Firearm Identification”. What is the purpose the lands andgrooves that comprise the rifling in a gun barrel?What is the difference between class characteristics and individual characteristics?
19 REVIEW How do you determine the caliber of a gun? What are the four parts of a cartridge?
20 REVIEWPretend you recover a bullet from a crime scene. How could you determine what kind of gun fired that bullet?
21 REVIEWWhat type of individual characteristics can be used to match a shell casing back to an individual gun that fired it?