1. Ballistics

2. What is Forensic Ballistics
Ballistics: The Science of the mechanics that deals with motion, behavior, and effects of projectiles
Forensic Ballistics: Science of analyzing firearm and weapon usage in crimes
Firearm Identification
Firearm components
Ammunition/Ammunition components
Toolmark analysis

3. What are Projectiles?
Projectiles: An object propelled through space an exertion of force that ceases after launch
Bullets, gravity bombs,
rockets, scrape metal

4. Kurt Cobain (2/20/67 – 4/5/94)

5. What is a Ballistic Body?
Ballistic Bodies are those that are free to move, behave, and be altered or modified in appearance and contour by ambient conditions, substances, and forces.
Ambient = surrounding
Contour = path
Example: Pitching a baseball

6. Ballistic History 9th century A.D. - Chinese discover gun powder
Potassium Nitrate (KNO3), charcoal, sulfur
Expands to 6 times its size when heated
Fireworks and cannonballs
14th century A.D. – Europe
Matchlock guns
Contained a barrel and wick on a piece of wood
18th century A.D. – Europe
Cartridges: case that holds a bullet, primer powder, and gun powder
Bullet: pointy projectile that is released when a firearm is discharged

7. Samuel L. Colt
1835: Colt creates the first firearm that can be shot multiple times without reloading

8. Ballistic History In Court
1902: 1st court case involving firearms evidence
Oliver Wendell Holmes proved
murder weapon by test shooting

9. Alphonse Gabriel Capone a. k. a. “Scarface” & the St
Alphonse Gabriel Capone a.k.a.“Scarface” & the St. Valentines Day Massacre

10. Ballistic History cont…
Calvin Goddard
Pioneer for Firearms Identification
Acquired data from all well-known gun manufacturers
Established database
Comparison Microscopes to compare and contrast test fires
Coined term “Forensic Ballistics”
Established the Bureau of Forensic Ballistics in NYC
1929: St Valentines Day Massacre
Event led to the opening of ballistic crime detection laboratory

11. Ballistic History cont…
1930: Earliest gunshot residue (GSR) test is performed
 It is principally composed of burnt and unburnt particles from the explosive powder – and possibly the components of the bullet, cartridge case, and firearm
1968: 1st use of scanning microscope for comparing GSR.

13. History cont… 1992: FBI established Drugfire database
Compiles details on bullet and cartridge markings
1996: U.S. Bureau of Alcohol, Firearms, and Tobacco (AFT) establish database for spent ammunition
2000: FBI and AFT begin merging databases

14. Types of Guns 1. Long guns Shot guns and rifles
Rifles  bullets
Shot guns  Small round pellets (shot) or a single projectile (slug)
Require 2 hands for accurate firing

16. Types of Guns 2. Handguns One hand to operate Pistols  single bullet
Revolvers
Cylinder that holds the cartridges turns as gun is fired, allows for several cartridges to be fired in rapid succession
Holds 6 cartridges

17. Automatic Weapons Semiautomatic
Holds up to 10 cartridges into a magazine (clip)
1 bullet fired per pull of the trigger

18. Automatic Weapons Fully Automatic
Multiple rounds are fired when the trigger is held down

19. Anatomy of a Cartridge Bullet:
Projectile that is extracted from the cartridge
Usually lead or copper
Metal-jacketed, hollow-pointed, or plastic

20. Anatomy of a Cartridge cont…
Primer powder
Struck by firing pin
Pressure causes ignition
Flash hole
Delivers the explosive charge from primer powder to gun powder

21. Anatomy of a Cartridge cont…
Headstamp
Bottom of the cartridge casing
Caliber and Manufacturer info

22. Gun Ballistics From the time of shooting to the impact upon a target
Broken down into 4 different branches
Internal Ballistics
Transition Ballistics
External Ballistics
Terminal Ballistics

23. Internal Ballistics
Def: The study of the processes that originally accelerate the bullet
Example: The passage of a bullet through the barrel of a rifle

24. Rifling (Internal Ballistics)
Rifling are helical (spiral) grooves that are cut into a bore of a firearm
Bore: Interior of a firearm
Lands: Raised portion of rifling.
Grooves: Indented portion of rifling
Caliber: Diameter of the bore
Usually expressed hundredths of an inch or mm

26. Why Significant? (Rifling)
No 2 rifled barrels are the same
Even those manufactured by the same company
Lands and Grooves leave marks on the bullet
As unique as fingerprints
Wear and tear from machine
makes each gun unique

27. Why Significant cont… Increase Accuracy Increase Speed
Lands and grooves cause bullet to spin
Increase Speed
The faster a bullet spins the easier it cuts through the air, thus allowing it to travel faster

28. Transition Ballistics
Def: Study of the projectiles behavior once it leaves the barrel and the pressure behind the projectile is equalized
This accounts for the loud sound a gun makes when fired

29. External Ballistics Def: Study of the projectile through air and space
There are two main forces that act upon the projectile
Gravity: drops the bullet
Air resistance: decelerates the bullet

30. Bullet Movement (Ext. Ballistics)
Bullet Drop
3 feet over a distance of 500 yards
Bullet Rise
Bullet rises before it drops
Due to force from being fired
Rise can be up to about 14 inches

31. Bullet Drop and Bullet Rise

32. JFK Autopsy Pictures

35. Factors that would affect Bullet Movements
Gun Type
Bullet Weight
Weather conditions
How about for extremely long ranges (missiles)?
Coriolis Effect
Deflection of an object due to the rotation of the Earth

37. Terminal Ballistics
Def: Study of the interaction of the projectile with its target
Also referred to the stopping power when dealing with human or living tissue
Only relevant for smaller projectiles

38. 3 Classes of Bullets
Terminal Ballistics depends on the class of bullet
Maximum Accuracy
Maximum Damage w/Total Penetration
Maximum Damage w/Controlled Penetration

39. Total Penetration Bullets
Want to focus the most momentum on the smallest possible target
Armored targets/Large game animals
Tips are…
Sharp
Lead covered in metal coat
Resist Deformation

40. Controlled Penetration Bullets
Designed to inflict maximum damage on a living target
Designed to increase surface area upon impact
Expanding Bullets (Hollow Tip)
Sharp tips with nothing behind them
Covering opens up upon impact
Larger Hole
Slows Impact
“Mushroom” effect

41. 2. Fragmenting Bullets 3. Frangible Bullets
Designed to break apart upon impact
Differ from that of hollow points in that they do NOT stay in one piece
Used for small game
3. Frangible Bullets
Similar to Fragmenting…break apart upon impact
Differ: NOT hollow
Hostage Situations

42. Gun Shot Residue (GSR)
GSR = residues of smoke and particles of unburned powder carried sideways from the firearm by the expansion of gases as the bullet is fired.
Stick to shooter

43. Gun Shot Residue
Residue can travel out of the gun from distances of 3-5 feet
Sticks to both shooter and victim
Amount of GSR decreases as the distance between firearm and victim increases
Helps to determine distance between shooter and victim