Sunday, December 9, 2018

Gunshot Residue and Personal Carry Ammunition

In September 1997, after 8-1/2 years and four trials, Daniel Bias Jr. began a six-year prison sentence for murdering his wife. One of the key issues associated with the case was the presence or lack of gunshot residue on Lise Bias after the shooting. The defense attorney in Bias’s trial argued that Lise Bias died accidentally as she was pointing a pistol at her head: however, the prosecution argued that the lack of gunshot residue on Lise Bias's nightgown and head wound shows she could not have shot herself.

A prosecution witness and ballistics expert testified that the bullet that killed Lise Bias would have left a powder residue if it had been fired from any distance under 45 inches. However, ballistics testing on the ammunition Lise Bias’s wounds could not be run because the ammunition in the pistol that killed Lise Bias was ammunition that Daniel Bias had reloaded. As a result, there was no way of knowing if the cartridges were all the same reloads or not and therefore they could not be relied upon for gunshot residue (GSR) testing.

Per Massad Ayoob: Defensive shootings are often very close-range affairs in which gunshot residue from your muzzle is deposited on your attacker’s body or clothing. This can become a critical evidentiary factor if the other side insists he was too far away from you to endanger you at the moment he was shot.* With reloaded ammunition, the forensic examiner cannot verify distances because there is no un-biased sample to measure it against. The accused has literally manufactured the evidence; therefore, judge is unlikely to admit the reloaded ammunition as an exhibit in the trial.

Picture #1 below shows powder burns on a white t-shirt when I fired a 9mm pistol with the muzzle in contact with the shirt.

#1: Muzzle Contacting T-Shirt

From a distance perspective, the lead deposits in picture #2 is similar to what happens with gunshot residue. Closer shots deposit more material, while more distant shots deposit less. These are pictures of reloaded ammunition firing plated bullets. The rifling in the barrel will often cut the plating and the bullet will spray an extremely fine mist of lead as it initially leaves the barrel. Bullet “A” was 12 inches away, bullet “B” 24 inches, and bullet “C” was 36 inches from the t-shirt.
#2: Muzzle at 3 Different Distances
Picture #3 shows the same phenomena on cardboard with bullets fired from various distances. Picture #4 is gunshot residue deposited on a target from a pistol approximately six inches away.

#3: Muzzle Various Distances

#4: GSR Six Inches

What can we learn from this? GSR distance testing is often done with exemplar ammunition or ammunition that is identical to what was in your pistol. This is the primary reason to carry factory ammunition for personal defense. When you purchase this ammunition, try to buy several boxes from the same lot. Write the date you entered the ammunition into service on the box. Load all of your carry magazines with the same ammunition from the same box—do not mix ammunition lots or brands in your carry magazines.

After you load your magazines for carry, save at least five rounds in the box. If you find yourself in a short range defensive situation, the forensics examiner can use the ammunition sample from the lot that you have saved to verify distances with powder testing. If the prosecution objects to this, your attorney can request an independent sample from the manufacturer. Large ammunition makers keep samples for each lot for exemplar testing for 10 years. This is why keeping the box intact with the lot numbers is important.

This does not mean you must practice only with expensive carry ammunition, reloads can have a role in this process. Reloading your ammunition can provide a more economical practice round for matches and training if you can match the point of impact for your carry ammunition. For example, I carry the Hornady Critical Defense 135gr standard pressure 9mm round. My reloads with 135gr plated bullets closely match my carry round. In the picture below, you can see a 15-yard group with the Hornady Critical Duty circled in red and three groups of my reloads circled in black. I was shooting my normal P320 carry pistol with a Trijicon RMR06 red dot sight. I adjusted the RMR so the Critical Duty impacted in the center of the one inch square.  Good enough.

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15 Yard Groups of 3 Shots

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