Discharge Residue from Black Powder Ammunition

In previous casework in which the majority of the FDR particles contained potassium and sulfur, frequently at high levels, it was thought that the ammunition responsible probably contained black powder. In most of the cases the type of ammunition was not known, whereas in others the sampling and analysis of the residue from the interior of the spent cartridge cases confirmed the presence of black powder.

This posed the question "do potassium and sulfur always occur, often at high level in discharge residue particles from ammunition loaded with black powder?" In other words, from the presence and levels of potassium and sulfur can it be accurately predicted when black powder is used?

A selection of old ammunition was tested to confirm that the propellant was black powder. Results of a representative selection of SEM/EDX analysis of the undischarged black powder are presented in Table 20.8.

It is interesting to note the presence of lead, antimony, and mercury in some of the analyses. The mercury is almost certainly from the primer whereas the lead and antimony could originate from two sources: the base of the bullet or the primer. However, if they originate from the bullet it would be expected that they would occur together and that the lead level would be significantly greater than the antimony level. This suggests that the lead and antimony also originate from the primer.

Discharge residue particles from black powder ammunition were then examined. Table 20.9 gives representative results.

As antimony sulfide is widely used in primer compositions, sulfur is frequently present in discharge residue particles and can occur at major, minor, or trace level (see Table 19.5). Consequently the occurrence of sulfur at major level is not an accurate indicator of the use of black powder. The particles should be considered as a group and it is clear that the frequent occurrence of both potassium and sulfur at high level is strongly indicative of black powder. However, as can be seen from Table 20.9 the use of black powder does not necessarily yield overall high levels of potassium. Potassium does not normally occur at major level in FDR particles (see Table 19.5) and its presence at major level in any of the particles suggests the use of black powder.

Table 20.8 Analysis of Unburned Black Powder

Ammunition

Major

Minor

Trace

Comment

UMC 32-20

K, Pb, S

Pb, S, K

Si

Numerous

Pb, S

K

Si

Pb, S, K

Si, Zn

Pb, S

K, Si, Zn

Hg, K

Si, Cu, Zn

K, Hg

Cu, Si

Pb, S

K, Si

RWS .320

K

Pb, S, Cu

K

S

Pb, Si

K

Pb, Cu

S, K

Pb, Si

Pb, S, K

Si, Cu

Numerous

No head stamp

K

S

297/230 Morris

S

K

Numerous

K, S

Cu

RWS .380

Pb, S, K

Si

Numerous

S, Sb, K

Si

Pb, S

K

Si

RWS .450

S, Sb, K

Si

Pb, S

K

Si

Pb, S, K

Si

Numerous

S, Sb, K

Si

Pb, S, K

Cu, Zn, Si

Eley London .450

K, Pb, S

Si

Pb, S, K

Si

Numerous

K, Sb

S, Si

K, S

Pb

Si

S, Sb

K

Si

Note: See Glossary for firearms/ammunition-related abbreviations.

Note: See Glossary for firearms/ammunition-related abbreviations.

A potential problem arises whenever black powder ammunition is used in close range shooting, in that the particulate matter deposited in the vicinity of the bullet hole is nondescript and does not resemble smokeless propel-lant. Consequently its significance may not be realized and it is also difficult

Table 20.9 Discharge Particles from Black Powder Ammunition

Size

Table 20.9 Discharge Particles from Black Powder Ammunition

Size

Ammunition

Shape

Major

Minor

Trace

Comments

UMC 32-20

5.0

Oval

Pb, S

Si

Numerous

4.0 3.5

Kidney Sphere

Pb, S, Ba, Sb Pb, S

Si, Fe, Cu Si, Cu, Sb

No Hg detected

(Overall

2.0

Oval

Pb, S, Si, Ba

Ca

K, Fe, Cu

high S,

2.0

Oval

Sb, Si

Pb, S

Ba, Cu, Fe

trace K)

RWS .320

8.0

Irregular

Pb, S

Si, Cu

Numerous

4.0 3.0

Pb, S, K

Cl, Si, Ca

Fe, Cu, Ba

(Overall high K and S)

5.0

Sphere

Sb, Pb, S, Fe

Cl, K

Si, Cu

No head stamp

1.5

Oval

Pb, S

Si, Ti, Fe,

Numerous

297/230 Morris

Ca, Cu

(Overall

4.0 3.0

Irregular Oval

Pb, S

Cr

Si, Sb, Ti, K, Fe

high S, low K)

3.0

Sphere

Fe, Pb, S, K

Ca

Ni

8.0

Oval

K, Si, Ba, Ca, Pb, S

Fe

Si, Ti, Cu

RWS .380

7.0

Oval

Pb, S

Si, Ca, K, Fe, Ti

Numerous (Overall

5.0

Spherical

Pb, S, K, Ca

Si, Ti, Fe, Cu

high S, low K)

3.5

Oval

Pb, S, Ba

Sb, K, Si

Fe, Cu

7.0

Kidney

Ba, Si, Ca

K, Fe

3.0

Triangle

Pb, S

K, Fe, Cu

RWS .450

10.0

Irregular

K, S

Numerous

3.0

Spherical

Pb, S, K, Cl

Si

Fe, Cu

(Overall high K and S)

5.0

Oval

Cl, K

Si

12.0

Oval

Sb, Ba, Pb, S

Si

K, Cu, Fe

12.0

Irregular

S, Pb, K, Fe

Cl

Cu, Zn

Eley London .450

4.5

Spherical

K, S

Numerous

2.0 8.0

Oval Irregular

S, Pb, Sb Pb, S, Cl

K, Ca, Si

Fe, Cu, Cl Fe, Cu

(Overall high K and S)

2.5

Oval

S, Pb, K

Cl, Si

2.0

Oval

S, Sb, Ba

Cl

K, Cu, Fe

Note: See Glossary for firearms/ammunition-related abbreviations.

Note: See Glossary for firearms/ammunition-related abbreviations.

to see on dark surfaces. If found it should be examined for potassium and sulfur for confirmation of black powder.

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