Physical Sciences: Firearms Unit & Documents Unit

3D laser imaging of bullet trajectories

Trajectory describes the curved path of the projectile from the muzzle to the target surface. Trajectory measurement involves determining a projectile’s directionality and may include measuring its angle of impact.

To evaluate the use of 3D laser imagining technology as a tool to enhance the objectivity of bullet trajectory estimation relative to the traditional trajectory method as described in Firearms procedure TOR-PS-FT-24.6.

Working with project leads to conduct test-firing in the CFS firing range, using a Glock firearm and full metal jacket ammunition. Four target types will be used (drywall, automotive door, wood and automotive car seat with a head rest). Three to five incident angles will be used for each target type. All shooting will be completed using two working days in the firing range and all trained scientists will be included in some portion of the testing. Rigs will be used to secure the weapon and the targets, which will allow the setting of three to five incident angles. Experimental measurement of incident angles will be accomplished by use of the current CFS method and the use of the 3D laser imaging system and software. Measurement of trajectories will be scheduled as time permits. All target objects will be securely stored at the CFS and will be permanently retained at the CFS to support future training needs.

3D laser imaging equipment, target rigs (to hold targets securely); expertise with laser imaging.

Glock firearms and ammunition, weapon rig and target material (drywall, wood, automobile door and car seat with headrest), firing range, staff expertise.

Comparison of three methods for measuring land and groove widths of fired bullets. [(a) comparison microscope and stage micrometer, (b) 3D microscopy, (c) an Integrated Ballistics Identification System (IBIS)]

A conventionally rifled gun barrel will have grooves that have been cut or impressed, and this imparts a spin to a bullet when fired. Each cut, or groove, is separated by a ridge of metal called the land. Together, these grooves and lands define the type of rifling inside the bore. The direction, width, and number of lands may vary by manufacturer. The rifling characteristics of a barrel are transferred to the bullet during the firing process.

PAttempt to establish whether or not one of the three methods can be objectively shown to produce superior results in the measurement of land and grooves.

The CFS is seeking a partner to design and conduct the experiment; statistically evaluate the results and publish the work. The land and groove impressions of approximately 100 bullets are to be measured using the Integrated Ballistics Identification System (IBIS), Comparison microscope using a stage micrometer and a 3D microscope.

None, but prior experience with microscopy, experimental design and statistical evaluation of data sets is valuable.

The CFS will supply all needed material, training, SOPs and access to required instrumentation. Analyses will be conducted on 100 bullets, which have already been test fired from handguns and rifles. A general rifling characteristics (GRC) database is available to evaluate the data-sets produced by the three analytical methods.