General: an expert in Forensic Weapon and Ammunition Examination identifies, typifies,
classifies and describes portable firearms and the ammunition intended for such weapons
according to the Weapons and Ammunition Act.
Comparative bullet and cartridge case examination
During the comparative bullet and cartridge case examination, an examination is conducted
into microscopically small mechanical damage (weapon marks) on components of ammunition
(bullets and cartridge cases) and cartridges. These marks are created when shooting
or chambering ammunition in a firearm. The marks are characteristic of or particular
to the firearm used and are consequently, highly indicative.
Connections can be established between each of the examined components of ammunition
and/or between those components of ammunition and a firearm by comparing the weapon
marks on bullets, cartridge cases and cartridges with each other. A special form of
comparative bullet and cartridge case examination is an examination of the found ammunition
components with a larger collection of stored bullets and cartridge cases from various
shooting incidents.
During the comparative bullet and cartridge case examination, the expert identifies
relevant weapon marks and compares these with the aid of a comparison microscope equipped
for this purpose. The discovered similarities and differences are recorded and interpreted.
The latter leads to a statement as to whether the findings are in line with the hypothesis
that ammunition components had been discharged in the same firearm or that a given
individual firearm had been used or that it was not used.
Weapon-technical examination for the purpose of reconstruction
During a weapon-technical examination, a weapon is examined for mechanical operation,
defects and failures for the purpose of reconstructing the causes of a shooting incident.
The condition and construction of the weapon are considered while taking into account
the actions alleged to have been performed with it. These acts largely concern the
possibility of accidental firing during throwing, falling, hitting or struggles.
The weapon is tested for sound operation. The examination consists of a thorough (microscope)
inspection for damage, signs of wear and tear or missing components. The safety mechanisms
that should be present have to be checked, followed by shooting tests and/or experiments
that can recreate the acts that have been suggested as possible scenarios. The expert
is able to establish, by means of inspection, assembly or disassembly an analysis
of faults and failures, and an estimation as to whether there is any true basis for
the proposition that the examined weapon fired by accident.
The forensic ballistics examination
The forensic ballistics examination consists of all four phases of ballistics: internal,
muzzle (or transitional), external and terminal ballistics. The latter two are particularly
relevant in connection with the direction of the shot, determining the firing distance
and the effect of the bullets on targets that have been hit.
Experiments are conducted during ballistics examinations with the aim of evaluating
the hypotheses proposed by the commissioning party concerning the shooting incident.
The questions that can be asked are highly diverse in nature.
External ballistics:
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– The expert can determine the projectile velocity (for example with a Doppler radar
or a light barrier) and precision of a weapon-ammunition system.
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– The firing distance can be evaluated by reconstructing the available data from the
crime scene (for example, the spread of buckshot).
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– Reconstruction of projectile trajectories.
Terminal ballistics:
The expert has to be capable and competent in the performance of all necessary experiments,
perform them or have them performed, and to process and interpret the data of a significant
number of measurements (statistically).
Legal domain: criminal law.