- 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
- 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
Bullet Design
Home > Characterization and Evaluation of Fired Projectiles > Microscopic Marks > Bullet Design
Accelerator ammunition: small bullet covered
by a plastic “sabot” or sleeve to fire
in a larger caliber firearm
Some bullet designs impact the ability to find and evaluate microscopic marks, including the following:
- Coated bullets are lead alloy bullets with a thin coating of another substance (not a jacket).
- Nyclad is an inert nylon coating. While this type of bullet will have impressions on the bearing surface after firing, they are typically less well defined and more difficult to measure.
- Copper or brass plated/washed bullets are covered with a thin alloy coating that can make reading dimensions more difficult because of their propensity for peeling.
- Teflon coated bullets retain very little microscopic detail of value for comparison purposes.
- Exploding bullets contain a primer or explosive and are designed to explode upon impact, resulting in an unreadable bearing surface.
- Frangible bullets are designed to disintegrate upon impact with a hard surface to minimize ricochet. No measurable bearing surface remains.
- Sabots are lightweight collars that allow smaller, lighter bullets to be fired. Microscopic marks are found on the sabot but not on the bullet.
