GSR
Definition
Gunshot residue. The mix of particles ejected from a firearm on discharge, composed of primer metals (Pb, Ba, Sb), propellant residues (nitrites, nitrates, nitrocellulose, nitroglycerin) and bullet / cartridge metals (Pb, Cu, Sb, Sn).
- Full form
- Gunshot residue
- Primer metals
- Lead, barium, antimony
- Propellant residues
- Nitrites, nitrates, nitrocellulose, nitroglycerin
- Other source metals
- Lead, copper, antimony, tin from bullet/cartridge
Common questions
Why does GSR include metals from more than just the primer?+
Discharge vaporises material from several components at once, the primer compound, the propellant charge, and the bullet and cartridge case metals, so the residue cloud is a mixture rather than a single substance. This is why analysts look at both elemental composition and particle morphology together.
Why has GSR analysis had to adapt to newer ammunition?+
Many manufacturers now produce lead-free or heavy-metal-free primers to reduce environmental and health exposure, which removes the classic lead-barium-antimony signature that older detection methods relied on, pushing laboratories toward broader elemental panels and particle-morphology criteria.
Related terms
- ASTM E1588
- ASTM International standard practice for gunshot residue analysis by scanning electron microscopy with energy-dispersive spectrometry. Defines particle classification (characteristic, consistent-with, indicative), morphology...
- Dermal Nitrate (Paraffin) Test
- Historical test where molten paraffin was cast on the suspect's hand and the cast was sprayed with diphenylamine in sulphuric acid. Blue...
- Modified Griess Test
- A contact-transfer colour chemistry test for nitrite-containing propellant combustion residue. Sulphanilic acid undergoes diazotisation with nitrous acid (from NO2 on the target...
- Primer
- The small explosive cup at the base of a cartridge that ignites the propellant. Conventional primers use lead styphnate, barium nitrate and...
- SEM-EDX
- Scanning electron microscopy with energy-dispersive X-ray spectroscopy. The electron beam excites characteristic X-rays from each element present in the target grain, giving...
- Sintox Primer
- Lead-free, heavy-metal-free primer chemistry developed by RUAG. Uses diazodinitrophenol (DDNP), tetrazenes and potassium nitrate. Modern Sintox GSR particles contain Zn, Ti and...
- Sodium Rhodizonate Test
- Colour test for lead. The cloth is treated with sodium rhodizonate followed by buffer; lead deposits give a pink-to-red colour, confirmed with...