New Forensic Ballistics Study Examines How Decomposition Affects Bullet Identification
New forensic research examines how decomposition affects bullet markings, revealing challenges in firearm identification and ballistic evidence analysis.
A new forensic ballistics study has examined how prolonged decomposition can alter the microscopic markings on bullets recovered from human remains, potentially complicating efforts to identify the firearms used in homicide investigations.
Published in Forensic Science International on November 3, 2026, the research investigated whether bullets exposed to decomposition fluids could retain the distinctive markings needed for firearm comparison.
Researchers examined copper-jacketed 9 mm bullets fired from four different pistols: a Ruger P85, Beretta M92FS, Heckler & Koch USP, and CZ-75 Compact.
The bullets were inserted into stillborn piglet carcasses placed inside wheeled bins, creating confined decomposition environments where fluids could accumulate.
Over 110 days, researchers recovered bullets at nine intervals, beginning on day three and continuing through day 110.
The examination focused on striations, microscopic markings produced when a bullet travels through a firearm barrel. These patterns can help forensic examiners compare recovered bullets with reference bullets fired from a suspected weapon.
The results showed that decomposition caused corrosion, surface changes, and deposits that affected both general rifling characteristics and individual markings.
Bullets fired from the Beretta and Heckler & Koch pistols remained identifiable through day 19, while Ruger bullets could still be identified through day 48. Bullets from the CZ-75 deteriorated more rapidly.
The researchers also found that measurements used to narrow potential firearm models could change during decomposition, sometimes producing inconsistent database comparisons.
For investigators, the findings demonstrate why the condition of recovered ammunition must be considered when interpreting firearm examination results.
However, the experiment involved only four firearms and an animal decomposition model. Its findings cannot establish universal identification limits for bullets recovered from human remains.
The study provides preliminary evidence that decomposition conditions and firearm characteristics can influence the preservation of ballistic evidence, highlighting the need for further validation.