US Cartridge, 4.2 inch Smoke WP, M2, M2A1
These are Army, spin-stabilized projectiles fired from mortars, to produce screening or spotting smoke and incendiary effects. The projectiles are filled with white phosphorus (WP), some obsolete M2-series smoke cartridges have a substitute filler of titanium tetrachloride (FM) or sulfur trioxide-chlorsulfonic acid (FS).
WARNINGS: Protect the ignition cartridge primer while transporting an unfired cartridge. The primer is percussion-fired. Do not transport a leaking WP smoke cartridge unless it is immersed in water or embedded in wet sand. White phosphorus ignites spontaneously on exposure to air.
The M2 series cartridges have no extension. Propellant increments may be present around the ignition cartridge container and extension of unfired cartridges.
Currently manufactured projectiles have light green projectile bodies with one yellow band and light red identification markings. Projectiles of earlier manufacture have gray bodies with one yellow band and yellow markings.
Collaborative Ordnance Data Repository