1. Ballistics YouTube - Bullets in Slowmo

2. Ballistics The study of Ballistics involves the: Comparison of bullets and cartridge cases. Knowledge of all types of weapons. Restoration of serial numbers. Detection of gunpowder residue. Estimation of muzzle to target distance.

3. Ballistics Comparison of Bullets and Cartridge Cases Guns have two basic categories: Hand Guns Colt.45 Automatic 1911 A1 Pistol Rifles.30 Caliber M1 Rifle

4. Ballistics In addition, guns can be “rifled” or “smooth bored”.

5. Ballistics What is “rifling” and why is it necessary? Rifling is the machining of “lands” and “grooves” to the inside of the gun barrel. These cause the bullet to spin as it exits the gun barrel giving it stability and increased accuracy. Certain dimensions of this machining process give us the “caliber” which we are so familiar with.

6. Ballistics Bore – Is the distance from land to land. Lands – Is the area of the barrel not machined out when rifling. Grooves – Is the spiral cut out of the barrel, “rifling”. Caliber – Is the distance between lands, inches or mm.

7. Ballistics What type of evidence is Bore, # of Land and Grooves, and Caliber? Class or Individual. Answer: Class Remember Class evidence is associated with a particular group. There are plenty of 9 mm Glock hand guns floating around. Can this particular 9 mm Glock hand gun become Individualized? Answer: Yes After repeated firing the land and grooves become “marked” as the bullet travels in the barrel.

8. Ballistics These marking leave “striations” on bullets as they exit the barrel. Investigators can match bullets with specific guns by comparing these striations. It’s these striations which make each gun individualized. We can then say a particular bullet came from a specific gun.

9. Ballistics How do investigators get bullets for comparison? Ballistic Gel YouTube - Ballistic GelatinYouTube - Ballistic Gelatin Water Tank YouTube - PHY NYA Gun bullet in water tankYouTube - PHY NYA Gun bullet in water tank Bullets are compared and investigators can determine if a bullet was shot by a particular gun.

10. Ballistics Can bullet casings be compared and linked to a specific gun? Answer: Yes Just as the inside of a barrel leaves individual markings on bullets, the firing pin will leave individual markings on the cartridge. In each case, respectively, the bullets were fired by the same gun.

11. Ballistics Can investigators recover serial numbers from firearms? Answer: Of course they can. By applying certain acids onto gun surface where the serial number has been “erased” or scratched away, serial numbers become visible again.

12. Ballistics Can Gunshot Residue (GSR) provide investigators with valuable information? Answer: Do I need to answer this?. O.K. Yes. YouTube - Gun shot so slow you can see the bullet GunShot Residue is gun powder that does not burn when the bullet is fired.

13. Ballistics Gunshot Residue is ejected forward and backward, so the person firing the gun will have traces of the residue on his/her hand. This residue is easily detected and analyzed. Gunshot Residue can provide information about the muzzle to target distance.

14. Ballistics Because GSR leaves the muzzle in the shape of a cone, the diameter of the GSR left can give an indication of muzzle to target distance. Point Blank3”9” 15”21”

15. Ballistics Bullet Trajectory and Path Since bullets obey the laws of physics it is easy to determine their origin and distance traveled. This can be done by using dowels or lasers.