Presentation on theme: "Chapter 21 – Firearms and Tool Marks"— Presentation transcript:
1 Chapter 21 – Firearms and Tool Marks FRSC 7104Criminalistics IProfessor Bensley
2 FRSC 7104 – Chapter 21 Objectives After studying this chapter, the student should be able to: Recognize the various types of firearms and their basic components Recognize the various types of ammunition and their uses Understand how firearms evidence is collected and analyzed Describe the basic details of tool mark comparisons and firing distance determinations
3 FRSC 7104 – Chapter 21 Outline Introduction Total 14,916 14,224 13,752 FBI Uniform Crime Reports (2011)Murder Victimsby Weapon, 2007–201120072008200920102011Total14,91614,22413,75213,16412,664Total firearms:10,1299,5289,1998,8748,583(68%)(67%)Handguns7,3986,8006,5016,1156,220Rifles453380351367323Shotguns457442423366356Other guns11681969397Firearms, type not stated1,7051,8251,8281,9331,587Knives or cutting instruments1,8171,8881,8361,7321,694Blunt objects (clubs, hammers, etc.)647603623549496Personal weapons (hands, fists, feet, etc.)1869875817769728Poison1097115Explosives12412Fire13185987875Narcotics52344529Drowning16815Strangulation13489122Asphyxiation1098784Other weapons or weapons not stated1,0059999048728531 Pushed is included in personal weapons.
28 FRSC 7104 – Chapter 21 Outline Forensic Examinations of Firearms Class vs. Individual CharacteristicsLand Impressions:Left AUTO caliber FMJ bullets fired from a EAA Corp. pistolRight - 9mm LUGER caliber FMJ bullets fired from a BROWNING pistol.
29 General Rifling Characteristics Search CARTRIDGEMANUFACTURERTWISTL&GLANDGROOVE9MM LUGERAA ARMS INCR6.055.120ASTRA.053.128BERETTA.130HI-POINT FIREARMSINTERDYNAMIC.124LLAMA.054MAUSERSMITH & WESSON.056.122STAR.126SWD INC9mm LUGER bullet, fired from a 6/right rifled barrel, with a land width of .055mm and a groove width of .125mm. Firearm examiners will usually search with a plus or minus tolerance and the results of the search would look something like the data contained in the above table.