
The Spotting charge M3 has a 2 1/3 pound dark smoke filling and a black powder igniter. It is 5/8 inch longer than the Spotting Charge M1A1, but otherwise is like it. The M3, with its dark smoke filler, is well adapted for bombing practice over snow-covered terrain. The black powder igniter charge contains approximately 125 grains. It is used in the Practice Bomb M38A2.
OP 1664, Volume 2 - US Explosive Ordnance (1947)