- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- Introduction
- Objectives
- AFTE Knowledge and Ability Factors
- Measurement, Standards, and Accuracy
- Weight, Force, and Their Measurement
- Dimensional Data and Measurement Tools
- Muzzle Velocity of Bullets
- Stereo and Comparison Microscopes
- Small Tools and Supplies
- Imaging Equipment
- Field Support Equipment
- Computer-Based Technologies
- Firing Facilities
- Selected Bibliography
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Other Equipment
Home > Equipment and Instrumentation > Dimensional Data and Measurement Tools > Other Equipment
Calipers
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Left: analog calipers
Right: digital calipers
Calipers are used to measure the distance between two opposing sides of an object. It may be an inner dimension (such as the diameter of a hole) or an external diameter (such as the thickness of an object). The analog versions of calipers have a continuous dial with a needle from which to read results; digital versions provide an LCD display. Digital calipers also have a scale for manual use in the event of battery failure.
Steel Machinist’s Scale
Steel machinist's scale
For general utility, the use of a simple six-inch steel machinist’s scale can be helpful in making some types of measurements, such as barrel length. It is most useful if it has both English and metric units. The English units should include tenths of an inch as well as the standard increments.
MP 6 Optical Projector
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MP6 projecting measuring device –
righthand image shows unit in use
Although this optical projector was designed in the 1970s for measuring land and groove impressions, it can also be used for measuring bullet diameter and other small items. The first production model was used to support the FBI Laboratory in the massive data input phase in the assembly of the general rifling characteristics file. Although no longer manufactured, these are still in use.
