2-13. OPERATION OF AUXILIARY EQUIPMENT-Continued.
Ensure arming switch is off (lamp not lit) before unloading grenades from
Never place your body in front of dischargers when unloading grenades from
Remove grenades from dischargers and storage bins.
Return grenades to metal ammunition storage boxes.
Replace canvas covers over dischargers.
Misfire and duds.
Misfire. A misfire is the failure of grenades to be launched from grenade discharger barrels. When a
misfire occurs, make two additional attempts to fire the grenade (see para. 2-13c(6)). If the grenade
still remains, attempt to fire the grenade from another grenade discharger barrel. If grenade remains,
treat as a dud.
Duds. A dud is a grenade that has either failed to be launched from grenade discharger or has been
launched but failed to burst. Place dud in an empty ammunition storage box as referenced in TM
60E-3-2-3 and dispose of in accordance with local SOP.
Description. UKL8A1 RP screening smoke launcher grenades are used with the M239 grenade
launcher. They are filled with a red phosphorus and butyl rubber mix. Each grenade is approximately
2.625 in. (58 mm) in diameter, 7.281 in. (185 mm) long, and weighs approximately 1.5 lb (0.68 kg).
Function. A grenade is propelled from the discharger barrel when electrical current at the firing
contact ignites the fuze. The fuze ignites the propellant charge and a delay composition and, in-turn,
the gunpowder bursting charge. This bursts the rubber case and ignites the red phosphorus/butyl
rubber composition to produce an immediate smoke cloud.