Ballistics and Explosives

1. Ballistics and Explosives

3. Ballistics  �The science of the motion of projectiles, such as bullets from a gun. It is divided into three branches: interior ballistics, exterior ballistics, and terminal ballistics. Interior ballistics studies the projectile in the gun while exterior ballistics studies the projectile in and through the air. Finally terminal ballistics is the study of penetration of solids by the projectile million (Silvia, 1999. p. 69-70).

4. History of ballistics Charles Waite considered father of forensic ballistics Opened private lab in New York City named The Bureau of Forensic Ballistics in 1927. Phillip Gravelle and John Fischer were his partners along with Dr. Calvin Goddard .

5. Calvin Goddard In the late 1920�s, the work of Calvin Goddard brought the FBI (formally named in 1932) even more fully into the application of science to detective work.� Goddard, a pioneer in forensic ballistics, was instrumental in the opening of the Scientific Crime Detection Laboratory, then affiliated with Northwestern University, in Chicago.� The Bureau learned much from Goddard�s lab and it supported many of the efforts made by this organization over the next several years.

6. Bullets recovered from the bodies

7. Goddard and his comparison microscope

8. Modern Comparison Microscope

9. The Bullet.

10. Common types of rounds

11. Proper Technique

12. 38 Caliber and 44 Caliber

14. How a bullet is fired The bullet casing or shell is also marked or �striated� when it cycles through a gun. A firing pin striking the primer leaves a specific mark in the back of the shell Commonly, a semi- automatic or automatic firearm will eject the casing on its own immediately after being fired The mechanism that ejects the casings will also create its own striations on the shell.

15. The Barrel rifling

16. Rifling and Striations Many modern guns have rifling in their barrels The rifling adds spin to a bullet, causing it to travel straight. Because the bullet fits the barrel exactly, the rifling of the barrel leaves marks, or striations on the bullet. Since each gun is different, the marks a particular gun makes on a bullet shot through its barrel is unique, like a fingerprint.

17. Striations Every gun leaves striations on every bullet and casing that travels through it. These striations are unique to each gun, no two are exactly alike. These striations are like fingerprints that can be compared and traced Obviously this is very helpful in identifying what weapon was used in a particular crime

18. Lands and Grooves

20. Rifling patterns http://www.firearmsid.com/Galleries/static/A_riflingIllustrations.asp

21. Comparison scope of lands and grooves match up.

22. What must be collected Of course evidence must first be collected from the scene. Shell casings may be found on the ground near where the shooter was standing Bullets may be found lodged in surrounding items such as trees, walls, the ground, or they may be found still lodged in the victim. If possible the gun may even be uncovered at the scene.

23. Compare their evidence The evidence must now be compared to other evidence. Bullets and casings can be compared to bullets and casings from other crimes or crime scenes using most often a microscope. If a weapon is found or seized, scientists can test fire the weapon and compare these new bullets and shells with bullets and shells from the original crime.

24. Firing pin marks

25. Comparison micrograph of firing pin marks

26. Firing pin drag marks

27. Extractor marks

28. Ejector

29. Exhibit 1 (cartridge case) could neither be identified nor eliminated as having been fired by Exhibit 2 (firearm). The above conclusion is reached if the cartridge case lacks sufficient action marks to be identified as having been fired by the questioned firearm or the firearm in question fails to produce reproducible individual characteristics on standards.�

30. Exhibit 1 (cartridge case) could neither be identified nor eliminated as having been fired by Exhibit 2 (firearm). All general class characteristics such as caliber and firing pin shape would have to agree.� The image below shows a comparison between two cartridge cases that lack any individual characteristics but have a similar general appearance.

31. Watertank

32. Water tanks � preserve the bullet In order to observe the striations in the bullets, scientists fire bullets into a tank of water. The water helps preserve the striations left on the bullet from the gun used. The scientist can then look at the bullet under a microscope and compare the striations to other bullets that have been used in a crime.

33. Balistics Gelatin used by the shooting industry to simulate soft body tissue, Ballistic Gelatin provides an alternative to live animal or cadaver testing.�

34. Exhibit 1 (cartridge case) was not fired by Exhibit 2 (firearm). This conclusion can sometimes be reached when the submitted cartridge case exhibits very good individual characteristics that are very dissimilar to those produced on standards.� However, consideration must be given to the possibility that the firearm in question could have changed significantly.� If all dissimilarities can be accounted for, a negative conclusion will be reached.� The comparison image below shows two cartridge cases that exhibit noticeably different breech marks and firing pin impressions.

36. Striae

37. The survey says� Based on the results of these tests, scientists can now prove or disprove weather or not two bullets were fired from the same gun, or weather or not a gun fired a certain bullet. This crucial evidence can often make or break a case in court, so long as it is presented in the right manner

38. Possible drawbacks Shotguns and revolvers Bullet expansion and deformation No two bullets are EVER the same Barrels, along with the whole firearm can be altered, switched, or destroyed.

39. Striations

40. Striations � Lands and Grooves

45. Types of bullets A full metal jacket bullet is a bullet encased in a copper alloy. A hollow point bullet is a bullet that has a hollowed out shape in its tip. A frangible bullet is designed to disintegrate into tiny particles upon impact to minimize their penetration. A rubber bullet and plastic bullet are designed to be non-lethal, and are used in situations such as riot control.

46. Bullet types Bullet types Bullet types and purposes Bullet type cross sections

47. Civil war bullets Round projectiles � not accurate past a short distance. Gasses blowing by the round sice it was not a snug fit. To remedy this a cloth was added around the round to make up any gap that existed.

48. Cavitation

49. Shotgun Slug vs. Shot

50. Bullet in body � X-Ray

51. Summary of wound types

52. General Features of Entrance Wounds a dirt ring around the wound caused by the bullet 'cleaning' itself off on the skin as it passes through fibers may be found in the wound from clothing covering the wound a smaller defect than the diameter of the bullet due to elastic recoil of the skin. Powder blackening may indicate direction of fire (ex. a circular zone of blackening from a shot fired at right angles to the skin surface, compared to an oblique zone from an oblique shot etc) stippling/ tattooing of the skin charring of the skin entry wounds caused by shots fired at a distance. Entrance wounds into skull bone typically produces beveling, or coning, of the bone at the surface away from the weapon on the inner table. In thin areas such as the temple, this may not be observed. Sternum, iliac crest, scapula, or rib may show similar features.�

53. General Features of Entrance Wounds Tangential entrance wounds into bone may produce "keyhole" defects with entrance and exit side-by-side, so that the arrangement of beveling can be used to determine the direction of fire.� Use of silencers (or "muzzle brakes" to deflect gas and recoil) may produce atypical entrance wounds. A silencer is a device, often homemade, fitting over the muzzle that attempts to reduce noise by baffling the rapid escape of gases. Entrance wounds may appear atypical at close range.

54. General Features of Exit Wounds A larger wound than the entrance wound, due to the bullet tumbling in it's passage through the body, and bony fragments being forced out through the skin can be of any size or shape, but are usually irregular (slit-like or square). May be similar to the entrance wound in size if the bullet was fired from a high velocity rifle shot at long distance (ex. a military rifle) a 'shored' exit wound occurs where the wound edges are abraded against an overlying object pressed firmly against the skin, as the skin is pushed out from the body by the bullet. The features were directly proportional to the KE of the projectile and the rigidity of the shoring material. �

55. X-ray of .38 to skull

56. X-Ray of shotgun pellets to abdomen

57. CT of head showing boney fragments pushed in to brain area

58. 9mm semi automatic

59. Revolver

60. Firearm Anatomy

61. Firearm Anatomy

62. How a weapon works Remington�s website 3D images and applets of how the firearm works http://www.remington.com/products/firearms/3-D/ How a revolver works http://people.howstuffworks.com/revolver2.htm

63. Pictures of all types of handguns Firearms Illustrations Bullet pictures Bullet comparison micrographs Cartridge casing comparison micrographs

64. Semi-auto rifle

65. Handgun vs. rifle bullet

66. Bullets after striking a target

67. Handgun Caliber Caliber is used to describe the size of a rifle or handgun bore and the size of cartridges designed for different bores. Caliber is usually measured as the diameter of the bore from land to opposite land and is expressed in hundredths of an inch, thousandths of an inch, or millimeters. For example, a .270-caliber rifle bore measures 270/1000ths of an inch in diameter between the lands and has a larger bore diameter than a .223-caliber rifle. However, there is no standard set for designating caliber. In some cases, the caliber is given as the diameter of the bullet, which is the distance between the grooves. Caliber designations sometimes have a second number that has nothing to do with the diameter. For example, the popular .30-30 is a .30-caliber cartridge, but the second number is a holdover from the days when the cartridge took 30 grains of powder. The "06" in .30-06 refers to the year (1906) it became the official ammunition of the U.S. military. Circles show bore sizes of common cartridges. Having the same bore size does not mean different cartridges are interchangeable.

68. Handgun Caliber Every rifle or handgun is designed for a specific cartridge. The ammunition must match the data stamp on the firearm. For example, there are several .30-caliber firearms that use the same bullet size but are designed for different cartridges (the .30-30, .30-06, .308, and the .300 Savage). If you cannot find the caliber stamped on the firearm, take it to a qualified gunsmith.

69. Handgun Caliber picture

70. Common Ballistic speeds Chart of cartridge size and speed obtained when fired

71. Shotgun Gauge Shotgun gauges are determined by the number of lead balls of a given diameter required to make one pound of that size ball. Thus 10 balls of 10 gauge diameter are required to make one pound of such balls, or 20 balls of 20 gauge diameter are required to make one pound, and so forth. This is the traditional, and very old, system. The actual (nominal) bore diameters of the various gauges are as follows: 10 gauge = .775 inch, 12 gauge = .729 inch, 16 gauge = .662 inch, 20 gauge = .615 inch, 28 gauge = .550 inch. The .410 is named for its nominal bore size, and is not a gauge at all

72. Measuring Up: Gauge vs. Caliber Shotgun sizes have always been measured in a somewhat roundabout way. You would think that the "12" in a 12-gauge shotgun corresponds to some linear measurement -- maybe inches or centimeters. But that's not the case. "12-gauge" means you can make 12 lead balls, each of equal diameter to the gun barrel, out of 1 pound of lead. This originated in the days when you would buy lead by the pound to make your own ammo. The gauge told you how many rounds you could make for the gun from 1 pound of lead.

73. Gauge sizing

74. Shotgun Parts

75. Shotgun vs. Rifle barrel

76. Choke types To control spread and impact point of shot

77. Shot Shell

78. Miscellaneous Ammo Breaching rounds - Shotguns are commonly used in the military to "unlock" doors when troops don't know what lies on the other side. Because traditional ammo tends to ricochet and may end up hitting the shooter or someone inside the room, breakable "breaching rounds" are often used. These shells contain a metallic powder that disperses on contact. Bean bags - Bean bags are used as shotgun ammo in crowd control situations, as in most cases they stun the victim but do not inflict lasting damage. CS gas grenades - Combat shotguns can be used to disperse tear gas and similar chemicals. Rock salt - Rock salt is a popular home defense ammunition because it reportedly causes severe pain but usually no permanent damage.

79. Alternative shotgun shells

80. Shotgun shell cross section

81. Shotgun Shot (pellet) sizing

82. Cell Phone gun Test fire video

83. The Dick Cheney Shotgun Experiment http://www.myscienceproject.org/shooting.html Alex Jones Chaney explanation and experiment Dick Cheney ballistic test results

84. Gun Safety Children should not play with guns Sniper training school � terminal balistics Shooting a bowling ball Bud Dwyer shoots himself during press conference 5/9/1994