Description
The only difference between the various Mods of the Tracer Mk 11 is in the construction of the relay housing:
Mod 0 - Housing is threaded.
Mod 2 - Housing is a push fit.
Mod 8 - Housing is an integral part of tracer body.
The relay housing contains three black powder pellets, which are ignited at the end of the burning of the tracer. The pellets, in turn, initiate the main charge of the projectile.
"Dark" Tracers Mk 11 are non-luminous; hence invisible day or night. They permit time of flight of 8.5 to 10.0 seconds (4,200 to 4,600 yards) before self destruction. A small, intense flash immediately precedes the flash from the bursting projectile. This ammunition was designed for night director-controlled fire. Lots are labeled HEI-SD(UK).
Hazardous Components
The "dark ignition" loading of the Tracer Mk 11 has the starter pyrotechnic of 65% barium peroxide and 35% powdered silenium. With the substitution of silenium for the magnesium, the tracer does not become visible until some 200 yards from the muzzle. 40mm ammunition using the "dark ignition" tracer is labeled HE-I-T-DI-SD(UM).
See Also
Nothing else to see.
Source(s)
TM 9-1300-203, Artillery Ammunition (1967)
OP 1664, Volume 1 - US Explosive Ordnance (1947)
