Gunshot Residue P 3

• What is gunshot residue primarily composed of?

  Powder from bullets and cartridge cases
• How does the distance from the muzzle affect gunshot residue patterns?

  Patterns depend on the distance at discharge
• What should be considered when interpreting gunshot residue on a person?

  Proximity to the firearm at discharge
• What does the absence of gunpowder residues indicate?

  It does not confirm non-discharge of firearm
• Where can gunpowder residue be found on a person?

  On skin or clothing of the shooter
• What are the main components of gunshot residue?

  Primer, gunpowder, cartridge case elements
• What is the function of a primer in firearms?


  To ignite the gunpowder
• What does a typical primer contain?


  Explosive, oxidizing agent, and fuel
• How far can primer residue be detected from the muzzle?

  Up to 200 meters
• Why are primer elements easier to detect in residues?

  They do not get as hot as gunpowder
• What are the major primer elements?

  Lead, Antimony, Barium
• What is the primary propulsive force in a cartridge?

  Gunpowder or propellant
• What is the composition of black powder?

  Carbon, sulfur, potassium nitrate
• What gas is produced from one grain of black powder explosion?

  200 to 300 cc of gas
• How does smokeless powder differ from black powder?

  Produces less flame and residue
• What is the typical composition of smokeless powder?

  Cellulose or glycerol nitrate
• What are the types of smokeless powder?

  Single, double, and triple based
• What is the purpose of gunshot residue examinations?

  To determine firearm discharge and range
• What is the detection limit for primer residue?

  Up to 30 feet
• What is the history of the paraffin test?

  Originated in Cuba for residue collection
• What is the principle behind the paraffin test?

  Detects nitrates from gunpowder residue
• What is the significance of blue specks in the paraffin test?

  Indicates presence of gunpowder nitrates
• What materials are needed for paraffin casting?

  Paraffin wax, absorbent cotton, bond paper
• How should the paraffin wax be applied during casting?

  Pour melted wax over hands thoroughly
• When should paraffin casting be performed?

  Within 72 hours of the incident
• Why should embalmed cadavers not undergo paraffin examination?

  Gunpowder nitrates cannot be extracted
• What is the detection limit for gunpowder residue on wounds?

  Up to 24 inches
• What is the role of a forensic chemist in paraffin casting?

  To conduct and examine the paraffin cast
• What happens to the skin during the paraffin test?

  Pores open to exude gunpowder particles
• What is the significance of the "tailing" characteristic in blue specks?

  Indicates positive presence of gunpowder nitrates
• What is the melting point range of paraffin wax?

  38-40 °C
• What should be done before applying paraffin wax?

  Wash hands without soap or detergent
• How should the paraffin cast be removed after cooling?

  Carefully peel off from the hands
• What is the purpose of using absorbent cotton in paraffin casting?

  To reinforce the wax during casting
• What is the first step in the paraffin wax casting procedure?

  Heat the paraffin wax until it melts
• Why should the paraffin wax be allowed to cool for a few minutes?

  To prevent burning the skin
• What should the subject do before the paraffin wax is applied?

  Wash hands without soap or detergent
• How should the subject's hands be positioned during the casting?

  Palms facing downward with fingers closed
• What is used to pour the melted paraffin wax on the hands?

  Spoon or tong with cotton
• What is the purpose of covering the hands with absorbent cotton?

  To reinforce the wax