Composition B (Comp B)
Definition
A secondary high explosive formulation of 60% RDX and 40% TNT by mass, melt-cast from the TNT matrix. Used in artillery shells, mortar rounds, anti-tank mines, and hand grenades. Detonation velocity approximately 7,900 m/s.
- Composition
- 60% RDX, 40% TNT by mass
- Manufacture
- Melt-cast, RDX suspended in TNT matrix
- Detonation velocity
- Approximately 7,900 m/s
- Common use
- Artillery shells, mortar rounds, anti-tank mines, grenades
Common questions
How is Composition B different from C-4 in a post-blast residue examination?+
Comp B is melt-cast and contains a large TNT fraction alongside RDX, so post-blast residue analysis typically detects both RDX and TNT (and their degradation products) together. C-4 is plastic-bonded RDX with almost no TNT, so residue dominated by RDX with little or no TNT points toward C-4 or a similar RDX-only formulation instead.
Why is the melt-cast manufacturing method significant for identifying munitions fragments?+
Melt-casting leaves characteristic voids, crystal structure and TNT-matrix residue that differ from pressed or extruded explosive fills, so fragment and residue morphology can help an examiner distinguish Comp B munitions from pressed formulations even when the charge itself has detonated.
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