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Firearms Examiner Training

Vaporous Lead Residues

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Vaporous Lead Residues

Cloud-like array of lead residues leaving the muzzle of a revolver
Cloud-like array of lead residues leaving the muzzle of a revolver
Courtesy of Jack Dillon (ver política de reutilización).

Vaporous lead (smoke) residues are characteristically deposited at closer ranges. These deposits are chemically detectable by an application of the Sodium Rhodizonate Test.

Results are useful in

  • determining the maximum distance of the vaporous lead deposits,
  • corroborating the results of the Modified Griess Test.

This type of residue is projected from the muzzle of a firearm as a cloud-like array. However, these smoke residues are projected only to a particular maximum distance. This distance can be determined by experimentation using the suspect firearm and ammunition in known-distance test firings.

Residues Consistent with the Passage of a Bullet

Residue consistent with the passage of a bullet (bullet wipe)
Residue consistent with the passage of a bullet (bullet wipe)
Courtesy of Jack Dillon (ver política de reutilización).

Holes found in objects, such as garments, with no accompanying particulate residues may appear consistent with the passage of a bullet. Positive results for the presence of any copper-bearing or lead-bearing residues (bullet wipe) from either or both of the Dithiooxamide Test and the Sodium Rhodizonate Test are consistent with the passage of a bullet.

 

 

Residues Consistent with the Discharge of a Firearm

Pistol firing showing residue from muzzle and ejection port
Pistol firing showing residue from muzzle and ejection port
Courtesy of Jack Dillon (ver política de reutilización).

In many instances, the discharge of a firearm will result in the deposit of particulate lead around a bullet hole. This deposit may be in the form of tiny solidified droplets resulting from the surface erosion of a bullet during its passage through the barrel, ejecta from a dirty barrel, or lead shavings from the surface of a bullet.

Such residues may be visible and are chemically detectable. However, these residues are not reproducible and therefore are not useful for a distance determination. On the other hand, they are consistent with the discharge of a firearm.

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