An FBI Ballistic Research Facility (BRF) report examining an alleged “uncommanded discharge” from a Sig Sauer M18 pistol—carried by a Michigan State Police officer—has reignited scrutiny of the firearm’s safety. The August 30, 2024, report, released this week via a public-records request, did not conclusively determine that the pistol fired on its own, but confirmed it was possible under certain conditions.
The incident occurred on July 31, 2024, when a Michigan State Police motor officer’s M18 discharged while still secured in its Alien Gear Rapid Force Level 3 holster. Witnesses confirmed the officer did not press the trigger, and that he had keys in his hand at the time. The weapon had a non-factory, modified trigger installed by a department armorer.
The BRF’s detailed testing found no internal abnormalities via x-rays or visual inspection. However, the FBI team discovered that inserting keys between the holster and the firearm could depress the trigger while holstered. The report stated that in conditions mimicking common law enforcement movements, it was “possible to render the Striker Safety Lock inoperable and ineffective… if complete sear engagement is lost.”
Despite these findings, the BRF also noted that the investigation “did not independently provide evidence of an uncommanded discharge.” In simpler terms, while failure scenarios could be recreated under controlled conditions, the specific pistol in question did not conclusively malfunction.
The M18 is part of the P320 platform, which is the subject of multiple lawsuits over claims of unintentional discharges. In response to the report, Sig Sauer Vice President Phil Strader confirmed that after reviewing the FBI’s findings, the company conducted additional testing. He said Sig engineers collaborated with the FBI and Michigan State Police, performing 560 attempts to force sear movement using 20 P320 striker assemblies—none of which resulted in a discharge.
Strader also noted that Michigan State Police continue to issue the M18 pistol, and reaffirmed that “Sig Sauer stands behind them.” The FBI’s follow-up report has not been released to the public.
