1. 16-5 Collection and Preservation of Firearms Evidence
Unit 16 - Firearms, Tool Marks, and Other Impressions

2. restoring serial numbers
Criminalist can restore serial numbers is removed or obliterated by grinding rifling or punching.

3. stamp zone
The metal crystals in the stamp zone are placed under permanent strain then extends a short distance beneath the original numbers.

4. chemical etching
Serial numbers can be restored through chemical etching.

5. Barrel
The suspect firearm should never be picked up by inserting an object into its barrel because this practice may alter the striation markings and test fire bullets.

6. Locate and record
Before unloading a suspect weapon record the weapon’s
hammer position
safety position
location
all fired ammunition
unfired ammunition

7. field investigator The primary concern of the field investigator
Protection of
class markings
individual markings
bullets and cartridge casings is
recovery and bullets and cartridge casings.