Topic 5: SCIENTIFIC EQUIPMENTS GENERALLY USED IN SOLVING FIREARMS IDENTIFICATION Flashcards
(99 cards)
1
Q
It is the most important instrument in forensic firearms examination because it analyzes and compares the evidence and the test fired cartridge case and bullet. The characteristics of the two specimens can be examined simultaneously. Thus, it is more comfortable on the examiner’s part to make a comparison. Moreover, the image viewed by the microscope lens can be stored and displayed on its monitor As such, more than one examiner can make the analysis and comparison.
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Digital Bullet Comparison Microscope
2
Q
- It records and stores the images viewed by the microscope lens.
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1) Built-In Digital Video Recording System
3
Q
- This will open and close the view in the eyepiece.
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2) Pull Lever For Trinocular
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Q
This connects the upper parts and lower parts of the bullet comparison microscope.
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3) Comparison Bridge
5
Q
This knob allows adjustment for a fine view of the specimen.
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4) Fine Focusing Adjustable Knob
6
Q
- This is to adjust the magnification of the image
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5) Magnification Power Knob
7
Q
- This is used to light objects on the stage plate.
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6) Illuminator
8
Q
- This is used to adjust the illuminator.
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7) Condenser Lever Control
9
Q
-A tube or a passage for lesser light.
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8) Fiber Optic Light Guide
10
Q
- The post of the lower and upper part
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9) Column
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Q
- This is used for adjusting the height of the plate for a better view of the specimen.
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10) Elevating Knob
12
Q
- This is used to select the lesser or brighter light.
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11) Light Selector
13
Q
- This allows the adjustment for dimmer light.
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12) Light Intensity Control
14
Q
-This allows the bullet comparison microscope to be placed in an upright position.
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13) Base
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- The overall switch for the bulb.
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14) Main Power Switch
16
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- Used to bring the specimen into approximate or near focus.
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15) Focusing Knob
17
Q
This is used to maneuver the stage plate movement back and forth
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16) X-Y Travelling Spindle
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Q
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19
Q
- This is used to swerve the stage plate in a different postion
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17) Stage Tilting Knob
20
Q
-This is a formed plate where the object is placed or mounted
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18) Stage Plate
21
Q
- This is the holder of the lenses
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19) Filter Holder
22
Q
This is used as a base holder of both stage plate
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Stage Holder Movement Knob
23
Q
-This is the holder of the magnifying lens.
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21) Threaded Objective Sleeve
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Q
- This is used to tighten the lock of the dividing line knob
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22) Bridge Fixing Screw
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- This is used to balance the view of two objects.
23) Dividing Line Knob
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- This is used to protect from dust and used as adjustment of a fine priam or dividing line
24) Dust Proof Cap
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- This is used to tighten the lock
25) Head Locking Screw
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-This is the base of both the dioptre and eyepiece
26) Binocular Head
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is a fine focus adjustment mechanism found riglit by the eyepiece It allows the adjustment of the focus for each eyepiece separately. It is helpful for people who usually wear glasses or have a different vision in each eye.
27) Diopter
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-This used for peeping to view two objects
28) Eyepiece
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This serves as a port where the connection from the computer or monitor is attached
29) Video Recording Interface
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The base is usually made of wood or one-ciglithyto one-quartepinch thick metal plates, Typically, the box is about ten feet long, 18 inches wide, and has a hinged lid at the top and firing port at one end. Bullets fired through the box are decelerated by cotton waste material, It is used to obtain samples or test bullets
2. Bullet Recovery Box
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is an optical microscope that provides a three-dimensional view of a specimen It is used to examine the individual markings of test-fired and evidence cartridge case and bullet
3. Stereoscopic Microscope
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Is the base of the eyepiece
Stereo Head
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-Used for peeping to view the two objects.
2) Eyepiece
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. The objective itself is usually a cylinder containing one or more lenses typically made of glass, its function is to collect light from the sample
3) Objective Lenses
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-It provides light to illuminate a specimen.
4) Lamp
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A formed plate where the object is placed or mounted.
5) Stage Plate
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-It is used placing the stereoscopic microscope in an upright position
6) Base
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- It is used to adjust the brightness of the light. Rotating clockwise increases the brightness, and anticlockwise decreases the brightness
Light Control Knob
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- These are used to hold the specimen in proper position.
8) Clips
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- This an adjustment knob for a fine view.
9) Focusing Knob
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This is used to take accurate measurements of the caliber of the bullet, cartridge case, and firearms, width of lands and grooves, depth of land, and height of grooves. It is more convenient to use because of its digital display.
4. Digital Caliper
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The upper jaws of a digital caliper are used for taking inside measurements such as the diameter of the cartridge case and bore of the firearm.
1) Internal Jaws
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- The lower jaws are used for measuring outside dimensions such as the diameter of the bullet, width of lands, and grooves, as well as the height of grooves and depth of land
2) External Jaws
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- The depth rod is used for measuring the length of the cartridge case and the length of the barrel for short arms
3) Depth Measuring Blade
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- This is where the measurement is automatically displayed.
4) LCD Display
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The measurement taken is shown on the main beam scale and the LCD
5) Scale
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-The LCD can be easily turned on or off using the on/off button.
6) Power On/Off
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- The zero button allows the user to set the LCD to zero. It makes the digital caliper a useful tool for taking comparative measurements. This feature also means that calibrating a digital caliper is very straightforward.
7) Zero Setting
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The lock screw secures the jaws into place, so the object being measured can be removed, and readings are taken
8) Lock Screw
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The user can convert their measurements from one measurement system to another by pressing the mm/inch button.
9) Metric/Inch Button
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is used to precisely adjust the measuring faces of the caliper (both sets of jaws and the depth rod). When taking outside measurements, the thumbscrew helps the user to get a tight grip on the material they are measuring
10) The Thumbscrew
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A ballistic chronograph or gun chronograph is a measuring instrument used to measure the velocity of a projectile in flight, typically fired from a gun. The modern chronograph consists of two sensing areas framed by rods topped by diffusing screens or artificial lighting above (or below) optical sensors that detect the bullet's passage. The time it takes the bullet to travel the distance between the sensors is measured electronically, from which velocity is calculated and displayed.
5. Modern Chronograph
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A pointed instrument used to mark bullets, shells, metallic fragments, and firearms.
6. Stylus
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Use to determine weights of bullets and pellets for possible determination of type, caliber and make from which fired
7. ANALYTICAL OR TORSION BALANCE
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is a device used for optical comparison and metrology. It is commonly used in manufacturing and quality control to compare physical objects, such as gears or molds, with their corresponding drawings or specifications.
magnifies and projects the image of the object for detailed inspection and measurement. Two fired bullets or two fired shells can be compared in one setting
8. CD-6 COMPARISON PROJECTOR
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refers to a manufacturer or company that specializes in the production of electronic guns of electronic markers. Electronic guns, also known as paintball markers, are devices used in the sport of paintball to propel paintballs at high speeds. They use electronic triggers and mechanisms for improved performance and control
ELECTRICAL GUN CRIMINAL JUSTICE EDUCATION MAKER
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is a measuring instrument used to determine the pitch or lead of a helix, such as screw threads or coils. It typically consists of a fixed reference edge or line and a movable component that can be adjusted to match the helical shape. are commonly used in engineering and manufacturing industries. For measuring the pitch of rifling/rifling
HELIXOMETER
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also known as a micrometer screw gauge, is a precise measuring device used to measure small distances or thickness with high accuracy. It consists of a calibrated screw mechanism that translates rotational movement into linear displacement, allowing for precise measurements down to the micron level
MICROMETER
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Small instrument sometimes used in examining the internal surface of the gun barrel in determining the irregularities inside the bore of the gun barrel. It has a tiny lamp the terminal portion and is inserted inside the bore for internal examinations.
12. ONOSCOPE
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is an optical instrument used to visualize and measure small surface defects or irregularities on translucent or transparent objects. It works by directing a beam of light onto the object and creating a shadow image that can be observed and analyzed. Shadowgraphs are commonly used in the inspection of glassware, lenses, and other transparent materials.
13. SHADOWGRAPH
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also known as a taper feeler gauge, is a precision measuring tool used to determine the taper or angle of a surface. It consists of thin metal leaves of varying thicknesses that can be inserted between two surfaces to assess the taper or gap. used for determining the bore diameter of the firearm.
14. TAPER GAUGE
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Determine the caliber of the bullet submitted and the type of firearm from which it was fired. The type of firearm used can be determined by examining the following class characteristics of the bullet submitted:
1. Given One Bullet
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Determine the caliber and the type of firearm from which it was fired. The type of firearm can be determined by identifying the following characteristics of the submitted cartridge case:
2. Given One Fired Cartridge Case
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Determine whether or not the bullet was fired from the suspected firearm. The following procedures should be considered:
3. Given a Bullet And Suspected Firearm
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Determine whether the cartridge was fired from the suspected firearm. The following procedures should be considered:
4. Given a Fired Cartridge Case And a Suspected Firearm
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Determine whether or not they were fired from only one firearm. The following procedures should be considered:
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5. Given Two Or More Bullets
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Determine whether or not they were fired from only one firearm. The following procedures should be considered:
6. Given Two Or More Cartridge Cases
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Determine the serviceability of the suspected firearm.
6. Submitted Firearm Only
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Be ready to explain methods, findings, and conclusions in court.
Expert testimony:
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Complie findings photographs, and analysis in a detailed forensic report
Prepare for report
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Use a comparison microscope to analyze striations on recovered bullets GSR testing: Analyze residue patterns to confirm firearm discharge.
Bullet comparison:
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Test-fire weapons to match rifling marks, chamber patterns, or ejector marks on casings.
Firearm examination:
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Log every movement of evidence from the crime scene to the lab and beyond.
Record transfers:
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Clearly label every piece of evidence with case information, date, and collector details.
Label evidence:
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Analyze bullet paths using tools like laser trajectory kits or stringing methods
Determine angles:
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Create a sketch or 3D model of the scene, marking the positions of firearms, casings, and bullet trajectories.
Map evidence:
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Package and seal garments for laboratory analysis.
Preserve clothing:
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Use GSR kits to swab hands, clothing, or nearby surfaces for residue.
Test suspects:
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Use soft materials to protect evidence from deformation.
Package individually:
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Use non-marring tools to recover evidence without damage.
Extract carefully:
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Identify projectiles or fragments embedded in walls, furniture, or bodies.
Locate and mark:
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Place each casing in a separate, labeled container to prevent scratches or mixing.
Package carefully:
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: Note the casing positions before collection.
Document orientations
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: Use markers or flags to pinpoint the positions of shell casings.
Mark locations
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: Collect and separately package any cartridges, rounds, or magazines.
Secure ammunition
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: Note serial numbers, safety settings, magazine presence, and chamber status.
Label and package
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The crime scene protocol for forensic ballistics involves a series of steps aimed at preserving of custody,
is an overview of the protocol: 1. Securing the Scene
Establish a perimeter: Use tape, barriers, or personnel to restrict access.
Log entries/exits: Record every person entering or leaving the scene to maintain integrity. Ensure safety: Check for potential hazards such as firearms, explosive devices, or hostile individuals
2. Initial Survey
Document observations: Record initial impressions of the scene, locations of weapons, shell casings, or projectile impacts.
Take photographs: Capture detailed images of the scene, ensuring all angles are covered,
Avoid contamination: Wear gloves, masks, and booties to avoid tampering with evidence.
3. Evidence Collection
Firearms
Make the firearm safe: Ensure the weapon is unloaded and document its condition before handling.
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Ensure the weapon is unloaded and document its condition before handling.
Make the firearm safe:
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Wear gloves, masks, and booties to avoid tampering with evidence.
Avoid contamination:
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Capture detailed images of the scene, ensuring all angles are covered,
Take photographs:
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: Record initial impressions of the scene, locations of weapons, shell casings, or projectile impacts.
Document observations
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: Record every person entering or leaving the scene to maintain integrity.
Log entries/exits
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: Check for potential hazards such as firearms, explosive devices, or hostile individuals
Ensure safety
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: Use tape, barriers, or personnel to restrict access.
Establish a perimeter
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: Use tape, barriers, or personnel to restrict access.
Establish a perimeter
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for forensic ballistics involves a series of steps aimed at preserving of custody, is an overview of the protocol
Crime scene protocol
