- 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
- Introduction
- Objectives
- AFTE Knowledge and Ability Factors
- Powders and Residues
- Examination
- Distance Determination
- Significance of Results
- Contact Shot
- Nitrite Residues
- Vaporous Lead Residues
- Residues Consistent with the Passage of a Bullet
- Residues Consistent with the Discharge of a Firearm
- Interpretation Challenges
- Reproduction of Results
- Nitrite Residue Patterns
- Shot Patterning
- Chemical Testing
- Shot Pattern Reproduction
- Selected Bibliography
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Nitrite Residue Patterns
Home > Gunshot Residue and Distance Determination > Distance Determination > Nitrite Residue Patterns
When reproducing patterns of nitrite residues, known-distance targets should be fired to produce patterns both smaller and larger than the evidence residue patterns. It is then possible to establish a range of distances for the evidence nitrite pattern. This range is generally at least a foot wide to account for possible variations in the ammunition type or resulting from evidence handling prior to receipt in the laboratory. Note that if a range is expressed as a conclusion, that the statement must include substantiated test fired patterns at each end of the range.
Click here to view examples of nitrite residue patterns from known distances
Scattered Nitrite Residues or Vaporous Lead
When reproducing results using these types of residue, the best distance determination is the maximum distance to which those residues can be projected, barring the presence of an intermediate object. The testing procedure is to produce data from two distances, one at which the particular residue is always found and the distance at which the residue is never found. This approach establishes a range that determines maximum distance.
The minimum distance is established based upon the results of the examination of evidence. At least three test shots are fired at each known distance. This will account for variations that may be present.
| Distance Determination Using Nitrite/Lead Residue Test | |||
| Distance (Feet) | Test 1 | Test 2 | Test 3 |
| 5 | present | present | present |
| 6 | present | not present | present |
| 7 | not present | not present | not present |
Based upon the results in the above table, a range of five to seven feet is established as the maximum distance to which this particular type of residue is projected.
