Bullet and Toolmark Analysis

Bullet and Toolmark AnalysisEverything you always wanted to know, but were afraid to ask . . .

Firearms Identification

Firearms Identification

A discipline mainly concerned with

determining whether a bullet was fired from a

particular weapon.

Firearms Identification

A discipline mainly concerned with determining whether a bullet was fired from a particular weapon.

Firearms Examiner

A gun.

Bullets in shells.

Gun Class Characteristics that you

can get off a bullet:

Gun Class Characteristics that you can get off of a bullet:# of grooves and lands

Gun Class Characteristics that you

can get off a bullet:# of grooves and lands

Direction of twist

Gun Class Characteristics that you

can get off a bullet:# of grooves and lands

Direction of twist

Caliber

Enough for a positive ID of a weapon?

Enough for a positive ID of a weapon?

Nope.

Comparison Microscope

Striation comparison

Firing Pin Impression

Breechblock impression

Obstacles to firearms identification

Obstacles to firearms identification

Obstacles to firearms identification

Shotguns are different.

See any rifling?

Some shotgun cartridges.

Shotgun cartridge.

Shotgun pellets.

Shotgun pellets.

Shotgun slug.

Shotgun slugs.

Shotgun firing.

CODIS, IAFIS . . . meet:

CODIS, AFIS . . . meet:

What else Firearms Examiners do

What else Firearms Examiners doThey do more!

Distance Determination!

Bang.

Contact

Stellate:

IR light can help visualize GSR on busy fabric:

Nitrite Residue patterns from known distances.

Firearms Do’s and Don’t’s

___ pick up a firearm by sticking something (like a pencil) into the barrel

and then lifting it.

DON’T pick up a firearm by sticking something (like a pencil) into the barrel and then lifting

it.

___ pick up a firearm by the checkered grip.

DO pick up a firearm by the checkered grip.

___ unload a firearm before you send it to

the lab.

DO unload a firearm before you send it to

the lab.

___ record the safety and hammer positions of a suspect weapon before unloading it.

DO record the safety and hammer positions of a suspect weapon before unloading it.

___ mark evidence bullets with your initials

on the side of the bullet.

DON’T mark evidence bullets with your initials

on the side of the bullet.