Firearms & Toolmarks Analysis
Evidence may not be visible to the naked eye
Which is the comparison of toolmarks to determine if they were produced by a particular tool and also determine what type of tool was used when no tool is available. In addition, training can be provided in serial number restorations, shooting scene reconstruction, firearm evidence recognition, collection and packaging.
Which is the comparison of ammunition components (bullets, cartridge cases, shot shells or other items) to determine if they were fired by a particular firearm.
Firearms function, operability, alterations, defects, conversions, modifications, accidental discharge
Cartridge manufacture and source determination of ammunition components
External and/or terminal ballistics calculations and determinations of the projectile’s trajectory, ricochet, penetration, etc
Distance determinations (muzzle-to-target determinations) from gunshot residue patterns or shot pellet patterns
Serial number restorations (firearms, motorcycles and other vehicles, bicycles, etc.) – anything with a identifying characters, numbers or markings that have been obliterated either intentionally or by wear or corrosion
Frequently Asked Questions
For Firearms and Toolmark Examinations
What if my circumstances or items are different from what is listed? Can it still be examined?
The best thing is to call and discuss your case. An experienced firearm examiner has a significant amount of insight into examining seemingly unusual evidence. In addition, they may have suggestions for testing or examinations of the evidence that are not readily apparent at the onset.
A well trained and experienced firearm examiner, with a strong science background and critical thinking skills is able to design experiments to test or recreate a particular situation, circumstance or occurrence. These experiments are necessary to support or refute statements with facts and data, not just opinions or anecdotes.
What is Firearms Identification?
Is it ballistics?
Well partly… Ballistics is the science of projectiles in motion.
It is usually divided into three parts:
- Interior Ballistics – which studies the projectile’s movement inside the firearm,
- Exterior Ballistics – which studies the projectile’s movement between the muzzle and the target,
- Terminal Ballistics – which studies the effect of a projectile’s impact at the target.
Ballistics is a term often confused with Forensic Firearms Identification.
What is a firearm?
What is a cartridge?
What is a bullet?
What is a pistol?
What is a semiautomatic pistol?
What is a revolver?
What is a rifle?
What is rifling?
What is a shotgun?
What is meant by gauge?
How is caliber defined?
It is a term used to designate the specific cartridge for which a firearm is chambered.
In firearms, caliber is the approximate diameter of the circle formed by the tops of the lands of a rifled barrel, typically expressed in hundredths of an inch (38 caliber) or millimeters (9mm caliber).
In ammunition, caliber is a numerical term, without the decimal point, included in a cartridge name to indicate the nominal bullet diameter.
What is an accidental discharge?
The inadvertent discharge of a firearm as a result of some failure on the part of the firearm. Accidental discharge is often caused by a safety device that was broken, deficient, compromised, or missing from the firearm that, if present and operative, would have prevented the discharge.
Can you test for an accidental discharge?
Yes, a function test of the firearm can be done. A function test is the examination of a firearm concerning its mechanical condition and operation. It is usually done to determine if all safety features or mechanisms are operable and/or if the firearm is capable of firing a cartridge.
What is a safety mechanism?
A device on a firearm intended to help provide protection against accidental discharge under normal usage when properly engaged. Such a mechanism is considered “on” when the position of the safety device is set in a manner to provide protection against accidental discharge under normal usage. Such a mechanism is considered “off” when it is set to allow the firearm to be discharged by a normal pull of the trigger.
A manual safety is one that must be manually engaged and subsequently disengaged to permit normal firing. An automatic safety is one that goes to the “on” position when the action of the gun is opened. A passive safety is in place (or “on”) until the trigger is pulled.
Can the distance from the firearm to the target be determined?
The process of determining the distance from the firearm, usually the muzzle, to the target is based upon patterns of gunpowder or gunshot residues deposited upon that target. Where multiple projectiles, such as shot, have been fired, the spread of those projectiles is also indicative of distance.
Are your able to test the velocity and penetration of a bullet, shot pellets or other projectiles?
A chronograph can be used to measure the velocity of projectiles. The penetration and behavior of projectiles can be determined experimentally by testing at various velocities and using different test media or substrates.
What ballistic testing media are available and why are they used?
Ballistic gelatin and ballistic soap are the most common media used. Both are designed to simulate living, soft tissue for use in wound ballistics studies of projectile behavior; meaning the penetration depth and deformation or expansion of the projectile.
Can the position or place of a person (the shooter or victim) in a scene be determined?
With a reconstruction of the trajectory or path of the projectiles, a muzzle to target determination, an ejection pattern determination, an examination of the evidence and the scene, the position(s) of the involved principals may be determined.
Can it be determined if a hole or defect has been caused by a bullet?
An examination of the hole or defect and chemical tests may indicate if it is or is not consistent with the impact or passage of a bullet.
Can you determine if a bullet struck or passed through something?
The bullet can be examined for trace evidence and if the condition is or is not consistent with it having struck or passed through something (like a wall, door, clothing, etc.).
Can you determine if a bullet or projectile has ricocheted?
A bullet or projectile may show physical effects or have on it trace evidence that indicates it struck an intervening object and was deflected or ricocheted.
What is Toolmark Identification?
Toolmark identification is a discipline of forensic science, which has as its primary concern to determine if a toolmark was produced by a particular tool.
What is a tool?
An object used to gain mechanical advantage. Also thought of as the harder of two objects, which, when brought into contact with each other, results in the softer object being marked by the harder object. The resulting damage or marks would be called toolmarks.
Whom should I avoid when seeking someone to perform forensic firearm and toolmark examinations?
Firearm enthusiasts, gunsmiths, firearms instructors and crime scene technicians. These individuals all have specialized knowledge in their fields, but they do not have the training and experience in forensic firearm examinations to conduct forensic firearms and toolmarks examinations, documenting evidence, preparing reports and testifying to their results.
Is there a professional organization for Firearm and Toolmark Examiners?
Yes! The Association of Firearm and Toolmark Examiners (AFTE). Their website: www.AFTE.org
The definitions given on this page are from the AFTE Glossary.
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