On the Formation of Quaternary Particles, Based on Lead–Barium–Antimony + Tin, Considered Characteristic of GSRs

The presence of tin in gunshot residue (GSR) particles from ammunitions used in short and long rifled firearms is well known and widely documented. Tin does not originate from the primer mixture itself but is typically linked to a thin disc-shaped foil placed over mercury fulminate-based primers to prevent embrittlement of the cartridge case and primer cap. However, this practice has not been previously reported or observed in hunting ammunitions. We designed an experimental protocol to investigate the formation of quaternary GSR particles containing Pb-Ba-Sb-Sn, following shots fired from a double-barrel shotgun using modified hunting ammunitions. These ammunitions were loaded with multiple pellets and included a thin tin foil over the primer's flash hole. Our results confirm that the tin foil is directly responsible for the origin and composition of the quaternary GSR particles detected on the collected stubs. Additionally, the hunting ammunitions market has recently seen increased production of environmentally friendly ammunitions, including shot pellets made of tin, tin alloys, or coated with tin. Our findings provide a foundation for further experimental studies into GSR from such eco-friendly ammunitions, especially in forensic investigations involving tin-containing pellets.