Lead-Free GSR
Definition
Gunshot residue produced by ammunition using non-lead primer formulations (SINTOX, Diazol, or other variants). Does not contain the conventional Pb-Sb-Ba three-element combination; requires alternative EDS criteria per ASTM E1588 2011 update and ENFSI 2023 guidelines.
- Cause
- Non-lead primer formulations
- Examples
- SINTOX, Diazol
- Missing signature
- No conventional Pb-Sb-Ba particles
- Standards affected
- ASTM E1588 (2011), ENFSI (2023)
Common questions
Why does lead-free ammunition complicate GSR analysis?+
Standard GSR identification by scanning electron microscopy relies on finding particles containing the classic lead-antimony-barium combination from a conventional primer. Lead-free primers produce particles with different elemental profiles, so a traditional criterion can miss a genuine discharge.
How do examiners adapt when lead-free ammunition is suspected?+
They apply updated elemental criteria that recognise the alternative primer chemistry, such as titanium, zinc, or other characteristic elements the specific lead-free formulation leaves behind, rather than searching only for the classic three-element particle.
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...
- Back-Scattered Electron (BSE)
- High-energy electron from the primary beam that has bounced elastically off a nucleus and exited the sample. BSE yield increases with atomic...
- Characteristic X-Ray
- An X-ray photon emitted when an outer-shell electron drops into an inner-shell vacancy created by ionisation. Energy is set by the difference...
- Energy-Dispersive X-Ray Spectroscopy (EDS)
- An X-ray detection method that simultaneously measures the energies of all characteristic X-ray photons emitted from the interaction volume, identifying all elements...
- FIB (Focused Ion Beam)
- A technique using a focused gallium ion beam to mill a specimen at a specific site-selected location, producing a TEM-quality cross-section with...
- Interaction Volume
- The pear-shaped region of specimen material within which the primary electron beam deposits energy and generates signals. At 20 kV in a...
- Secondary Electron (SE)
- Low-energy electron (below 50 eV) ejected from the top few nanometres of the sample when the primary beam knocks a loosely bound...
- Silicon Drift Detector (SDD)
- The current standard EDS detector type, using a reverse-biased silicon chip cooled by a Peltier element to achieve high count-rate capability (up...
- Sputter Coating
- Vacuum-deposition technique that lays a thin (5 to 15 nm) conductive layer of gold, gold-palladium or carbon onto a non-conductive sample (polymer,...
- Ultramicrotome
- A precision instrument for cutting sections of resin-embedded specimens to 60-100 nm thickness using a diamond knife, enabling TEM examination of the...
- ZAF Correction
- A software correction applied to raw EDS X-ray intensities to account for atomic number (Z), absorption (A), and fluorescence (F) effects within...