RPG Rocket Launcher

The Soviet RPG7 antitank rocket launcher using a PG7 tank rocket has been used during the terrorist campaign in Northern Ireland. It is a long weapon that sits on top of the shoulder when in use and "exhausts" to the rear of the firer. After incidents in which the RPG7 was used, the laboratory was requested to examine swabs and clothing from suspects, for discharge residue from the launcher. Because the "exhaust" from the weapon emerges a considerable distance to the rear of the firer, and the mechanism involved in its use, it was considered unlikely that residue would be present on the firer. To determine whether or not it was worthwhile examining swabs and clothing from suspects, a test was conducted and discharge residue particles from the RPG7 were examined. Discharge residues detected on the upper outer garment of the "firer" of the RPG7 are given in Table 20.6.

Discharge residue particles remaining in the launcher were also examined and the results are given in Table 20.7.

Table 20.6 Discharge Residue from RPG7 Rocket Launcher

No.

Size |i

Shape

Major

Minor

Trace

Particles

Comments

3.0

Sphere

Pb

Si

Cu, Ca, Cl, Al

7

2 x Fe, S trace

3.0

Triangle

Zr, Si

Ca

Fe, K, Cu, Cl

2

From primer?

2.0 x 5.0

Oval

Pb, Si

Ca, K, Al, Fe

Cu, Cl, Ti, Mg

1

2.0

Sphere

Cu, Pb

Sb, Fe, Zn

Al, Si, Cl, K

1

10.0

Spherical

Pb

Ba, Cr, Fe, Ca

Cu, Si, Al

1

3.5

Sphere

Pb, Ca

Si, Fe

Al, K, Mg, P, Cu

10

2.0

Spherical

Sb, Sn

Cu

Fe, Si, Cl, S, Al, Mg

3

Tin present

1.5

Spherical

Pb, Si, Ca

Cl, Fe, Ti, Mg, K

Al, Cu, Zn

1

2.5

Spherical

Pb, Ca

Ba, Si, Cl, Fe, K

Al, Mg, Cu, P, Zn

2

1.5

Oval

Pb

Cr, Ti, Ca, Si, Zn

Cu, Cl, K, Al, Na

1

Zn > Cu

3.0

Sphere

Pb, Fe

Ca, Si, Al, Cl

Ti, Cu, K, Mg

4

2.5

Oval

Pb, Cl

Ca, Si, Cu, Fe, K

Al, Zn, Ba, Mg

6

1 x Fe major

3.0

Double sphere

Pb, Si

Ba, Ca, Fe, Zn

Al, Mg, K, Cu, Cl

1

Zn > Cu

4.0

Spherical

Pb, Ca

Si, K, Cu, Fe

Al, Mg

21

1.5

Sphere

Sb

Fe, Cl, Si, Al

S, K, Cu, P, Mg

3

2.5

Oval

Pb

Ba, Si, Ca, Fe, K

Al, Zn, Cu, Mg

2

Zn > Cu

1.5

Spherical

Pb

Ca, Cr, Si, Fe

K, Cu, Zn, Al, Mg

1

3.5

Oval

Zn

Fe

Al, K, Si

3

Zn only

3.0

Spherical

Fe

Si

Cr, Al, P, Ti

6

The PG7 rocket is known to contain the following: black powder, a mix containing RDX explosive, hydrocarbon wax and an orange dye, PETN explosive, a mercury fulminate primer containing zirconium (see particles

Table 20.7 Residue in Discharged Warhead

Sample

Size F

Shape

Major

Minor

Trace

No. Particles

Comment

Booster

3.S

Diamond

Pb

K, Ca, Co, Fe, Zn

Cu, Si, Al, P, Mn

6

Zn > Cu

Propellant

3.0

Spherical

Si, S, Pb, K, Ti

Fe, Ca, Co, Sr

Cu, Zn

2

Sr from tracer?

7.0

Spherical

K

Si, Pb, Ca, Fe, Co

Zn

l

Zn only

Front end and outside

S.0

Rounded

Ba, Ti

S

Ti from paint?

3.S

Globular

Si, Ti

S, K, Ca, Sr

Fe, Cu, Zn

S

Sr from tracer?

Primer

2.0

Spherical

Ba, K, S

Al, Si, Fe, Cu

Pb

l4

3.0

Sphere

Ba, K, S, Cr

Al, Si, Ca, Cu

Zn, Pb

2

2.S

Spherical

Zr

Si, K, Ca

Fe, Cu

2

Zr powder?

l.S

Sphere

Al, Si, S, Pb, K

Ba, Fe, Cu

S

4.0

Sphere

Co, Si, Pb

K, Ca, Fe

Cu

2

Co from propellant?

l.S

Spherical

Pb, S, K

Al, Si

Fe, Cu

ll

2.S

Spherical

S, Pb, Co

Al, Si, K, Ca

Fe, Cu, Zn

6

Co from propellant?

4.S

Oblong

S, Pb, Co

Al, Si, Fe

Cu, Zn

S

Co from propellant?

3.0

Irregular

Co

K, Ca

4

Co from propellant?

l2.0

Irregular

Si, Ba

Cu, Sr, Al, Si

K, Ca, Fe

l

Sr from tracer?

3.0

Spherical

Hg

K, Ca, Sb, Fe

Cu

3

From primer?

in Table 20.7); an ignition powder containing barium nitrate, barium peroxide, magnesium, phenol-formaldehyde; a tracer composition containing strontium nitrate, magnesium, polyvinylchloride, phenol-formaldehyde with a yellow dye, an initial propellant charge containing NC, NG, EC, DBP, and a rocket propellant containing NC, NG, TNT (with some DNT), DPA, EC, DBP, hydrocarbon and salts of lead and cobalt. In addition the assembly contains steel, aluminum, and tin-coated copper parts, and is painted an olive drab color with black markings.

Apart from the possibility that residue was deposited on the firer in the act of firing there is also the possibility that subsequent handling of the launcher could yield distinctive residue. It is worthwhile examining the suspect for such residue.

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