Striation Marks
Definition
Fine parallel scratches on a fired bullet's surface produced by microscopic irregularities in the barrel's rifling. The pattern is individual to that barrel and changes as the barrel wears.
- Location
- Fired bullet surface
- Cause
- Microscopic irregularities in barrel rifling
- Individuality
- Specific to the firing barrel
- Stability
- Changes as the barrel wears
Common questions
Why are striation marks treated as individual rather than class evidence?+
Class characteristics like land and groove count and twist direction are shared across barrels of the same make and model, but the fine striation pattern comes from random microscopic tool wear on that specific barrel during manufacture, making it unique to it.
Does the striation pattern stay constant over the life of a firearm?+
No. Continued firing gradually erodes and alters the barrel's internal surface, so striation patterns from a weapon fired heavily over years can drift from earlier test fires, which examiners account for when comparing evidence recovered long after a weapon's last known use.
Related terms
- Cartridge Case Markings
- Impressions left on a fired cartridge case by the breech face, firing pin, extractor, and ejector of the firearm. Like rifling marks...
- Comparison Microscope
- Two compound microscope bodies connected by an optical bridge that presents one half of each body's image in a single split eyepiece...
- IBIS
- Integrated Ballistics Identification System: an image-based database platform used by multiple countries to store and compare fired cartridge cases and bullets from...
- Rifling
- The helical groove pattern cut into a firearm barrel that imparts spin to the bullet, stabilising it in flight. Rifling lands and...
- Wound Track
- The path of tissue disruption left by a projectile passing through a body. Consists of a permanent cavity (crushed tissue) and a...