 ATF National Laboratories
FIREARMS AND TOOLMARKS
ATF Laboratory Examinations
- firearms
- bullets, cartridges, shotshells
- toolmarks
- serial number/obliterated marking restoration
- gunpowder and gunshot residue patterns
- shooting reconstruction
- firearms identification
- the determination of whether a particular ammunition component was
or was not fired from a specific firearm to the exclusion of all others
- ammunition component = bullet, cartridge case, shotshell, shot, wadding
Examination of Firearms
- routine examinations
- all firearms are tested to see if they function as designed and are
safe to operate
- manufacturer, type, model and caliber information is recorded
- the firearm is test fired
- any firearm which is found to be "altered" during the routine
examination is sent directly to FTB for determination
- examination of ammunition components
Examination of Bullets
- routine examination
- determine manufacturer, caliber and type
- determine make of firearm which may have fired bullet
- bullet & firearm
- bullet undergoes routine examination & is compared to test fire
from firearm
Examination of Cartridge Cases
- routine examination
- determine manufacturer, caliber or gauge
- determine make of firearm which may have fired cartridge
- cartridge case & firearm
- cartridge case undergoes routine examination
- cartridge case is compared to test fire from firearm
- live cartridges
- determine if bullet has been loaded, extracted and/or ejected from
a firearm & type of gun it may have been worked through.
Examination of Shot
- determine size only
- it is impossible to identify shot to a particular shotgun
Examination of Slug
- determine size and gauge
- some slugs can be identified to a particular shotgun
Examination of Wadding
- determine gauge and manufacturer of shotshell
- some waddings can be identified to a particular shotgun
Examination of Casing
- determine gauge, manufacturer of shotshell
- possibly determine make of shotgun which fired the casing
Packaging & Shipping
Firearms
- shipping boxes are available from:
ATF Distribution Center
P.O. Box 5950
Springfield, VA 22150-5950
(703)455-7801 (to place an order)
- Box Size
| item # |
size of box (inches) |
| m 3000.11 |
36 x 10 x 10 |
| m 3000.12 |
20 x 16 x 8 |
| m 3000.13 |
16 x 8 x 41/2 |
| m 3000.14 |
36 x 9 x 51/2 |
- If fingerprint exams are requested, use plastic ties to secured gun
to box.
- Ship in "safe" condition
- unloaded
- breech open
- safety strap through the barrel, chamber or breech
- Ship via Federal Express
- Every attempt should be made to unload guns. If a gun that is loaded
must be shipped, notify the lab, document this in your transmittal letter
and properly mark the shipping box.
Ammunition
- Do not attempt to mark the bullet in any way
- Ship via Federal Express
- Never ship live ammunition through the U.S. Mail!
- Revolvers: package rounds separately and note where each one was positioned
in cylinder (especially important for round in hammer position)
- Fired Components
- package individually to protect markings
- Ship via Federal Express
Examination of Tools
- Defintion: the examination of transfer marks created by a hard object
(tool) against a softer object and the comparison of these marks to tools
which may have created these markings.
- Routine examinations
- type and/or design of tool used to create impression
- size and/or specifications of tool used to create impression
- any unusual features of the tool
- type of action the tool employed
- value of the toolmark for comparison purposes
- Toolmark and suspect tool
- determine if suspect tool is of the same class of tool which made toolmark
- microscopic comparison of toolmark with a "test mark" made
by suspect tool
- Fracture matches
- determination of whether two items were once a single unit
- Pressure/Contact
- determination of whether two objects were ever in contact with each
other
- Lock and key
- examination to determine if a key fits a particular lock
- examination of a lock to determine whether it is in a locked or unlocked
mode
- determination of whether an attempt was made to open a particular lock
with an improper implement
Packaging & Shipping of Toolmark Evidence
- All toolmark evidence and suspect tools should be individually packaged
in sealable containers (paper bags, ziplock bags).
- Do not make any test marks in the field, submit the actual suspect
tool.
- Label all toolmarks which should not be examined (ex: tools used or
wires cut used by agent, bomb tech, etc.)
- serial number/obliterated marking restoration
- the application of magnetic, chemical, electrolytic and/or thermal
techniques to a metallic object in order to reveal an obliterated mark.
- all fully recovered serial numbers will be reported and should be searched
by the agent through: The National Crime Information Center -and- the Treasury
Enforcement Communications System
Shooting Reconstruction
- Upon request, the Firearm Unit will respond to scenes and:
- Determine shooting position(s)
-and-
Determine the trajectory angle(s) of any fired projectiles
- These findings along with the analysis of photographs, and evaluation
of victim/witness statements, will assist the agent in developing possible
scenarios/sequences of events at a crime scene involving a discharged firearm.
- Determination of firing distances
- All submitted garments will undergo a series of visual, microscopic,
and chemical tests to determine if and where any gunpowder remains.
- The submitted firearm will be test fired at various known distances
towards a test fabric.
- The resulting gunpowder patterns remaining on the test fabric will
be compared to the original garment in order to determine a firing distance.
Packaging of Evidence
- Air dry all garments prior to packaging.
- Wrap each piece separately in paper or place in paper bag.
 Reprinted with permission.
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