Analysis of a Baton Round

As a consequence of a case in which the suspect alleged that the FDR on his person originated from contact with the inside of a police vehicle, from which baton guns had previously been fired, it was necessary to conduct a detailed examination of the baton round and the crime ammunition.

Antimony was detected in the residue particles on the suspect and it was known that the baton round does not have antimony in the primer. However, it was required to prove that there was no antimony in any part of a baton round. Analysis of the baton round revealed that the cartridge case was

Table 20.14 Discharge Particles from Ammunition with Antimony-Free Primers

Ammunition

Ammunition

Pb,

Ba,

Pb,

Pb,

Ba

Pb

Firearm

Head Stamp

Details

Sb, Ba

Ca, Si

Ba

Sb

Only

Only

.22LR

U

Unjacketed.

ND

ND

ND

20

ND

36

Walther

Brass wash

pistol

Pb-only primer

9 mmP Star

D144

FMJ. Cu

7

19

15

2

ND

15

pistol

washed Fe jacket. Pb, Ba primer

.30 Ml

LC68

FMJ. Cu

18

ND

12

2

6

22

Winchester

washed Fe

carbine

jacket. Pb, Ba primer

ND = not detected aluminum with trace amounts of iron and silver, and it was painted black with a white band. Analysis of the black paint showed the presence of aluminum, silver, bromine, chlorine, chromium, iron, potassium, nickel, sulfur whereas the white paint revealed titanium only. The discharged primer residue gave lead and barium at major level, aluminum and silicon at minor level, and tin and copper at trace level. The primer cup was tin with a trace of copper and silver, and the red lacquer on the exterior surface of the cup contained silicon and tin. The black powder propellant was housed in a plastic casing on which was painted a green dot. Analysis of the propellant revealed potassium and sulfur at major level, and silicon and iron at trace level, and the green paint gave lead, sulfur, potassium at major level, chromium, chlorine at minor level, and barium, titanium, iron at trace level. The plastic baton itself had chlorine, iron, barium at major level and calcium, silicon at trace level on its outside surface, and chlorine at major level and calcium at trace level on its inside surface. The end cap was painted cream and analysis showed the presence of sulfur, silicon, calcium at major level with iron, potassium, silver, aluminum, and bromine at trace level.

No antimony was detected anywhere in the baton round. Test firing the baton gun and sampling the firer also failed to reveal the presence of antimony in the discharge particles. Tin was present in some of the discharge particles.

The crime ammunition was 7.62 x 39 mm caliber Yugoslavian nny 82. Analysis of the components gave the following results.

Propellant: Single based with DPA, EC, a phthalate plasticizer, camphor Unburned Si, Pb at major level, Ca, Cu, S at minor level, Ba, Fe, K at trace level

Burned K and S at major level Cartridge case and primer cup: Cu with a trace of Zn Discharge primer residue (elements listed in descending order): (inside of primer cup) Sb, Sn, S, Cl, Hg, Cu, Zn, Fe, K, Ca (inside of cartridge case) Sb, Sn, K, Cl, Cu, S, Zn, Fe, Hg Bullet jacket: Cu at major level with Zn at minor level and Fe, Cl at trace level

Bullet core: Pb with trace levels of Sb, Si

Lacquer (primer): Pb at major level, Ti, Cr, Si at minor level, Fe, Mn, Cu, Cl, K, Ca at trace level

Black sealant between bullet and cartridge case: Cu, Pb, Cl at major level, Zn, S at minor level, Si, Sb, Fe, K, Ca at trace level

It is interesting to note that the primer appears to be based on mercury fulminate, antimony sulfide, and potassium chlorate, that is, mercuric and corrosive, and that the ammunition was manufactured in 1982.

There is no lead or barium in the primer yet discharge particles from this ammunition frequently contain lead, antimony, and barium. The lead and barium must come from other components in the ammunition (bullet core/propellant) and/or from contamination in the firearm. Tin was also frequently present in the discharge particles and originates from the tinfoil disc used to seal the primer cup in mercury fulminate primers.

The absence of antimony in the baton round discharge particles proved that the residue on the suspect did not originate from this source.

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