Mercury-containing ammunition residue

The particle classification scheme is based on modern primed ammunition and consequently mercury fulminate-primed ammunition is not included. Mercury-containing particles from the discharge of mercury fulminate-primed ammunition are rarely detected in casework. Discharge residue from such ammunition was tested in an effort to provide an explanation for this. Discharge particles from Sintox-primed ammunition was also examined with a view to anticipating future problems the criminal use of... 

To determine the frequency of occurrence of mercury-containing particles in FDR, promptly collected residue from the discharge of mercury fulminate-primed ammunition was examined. Results are given in Table 22.1. In the first firing a small proportion of the particles also contained one of the following elements cobalt (trace), magnesium (trace), nickel (trace), and phosphorus (minor and trace). 

In casework in which discharge residue particles were detected, and in which the ammunition involved is known to contain mercury, very few, if any, of the particles contained mercury. This has been noted over many years and in numerous cases. Possible reasons for this could be the volatility of mercury and its compounds, or decomposition of the mercury fulminate and the loss of mercury through amalgamation with zinc in the primer cup/car-tridge case. It is not uncommon, when firing old ammunition with mercury fulminate primers, for some of the cartridge cases to crack, due to embrittlement of the brass caused by mercury amalgamating with the zinc. 

This supports the proposition that anything present in a round of ammunition can make a contribution to the composition of the discharge residue particles. The presence of tin in any of the discharge particles is an indication that the primer contains mercury, the tin originating from the tinfoil disc used to seal mercury fulminate. (Tin is also present in some modern ammunition components, for example, Sellier Bellot, and it is present in some propellants.)... 

An ancillary test involved examining discharge residue particles from the ammunition used in the mercury distribution tests. Approximately 260 particles were examined of which 8 contained mercury (about 3%) at minor or trace level. 

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