A Primer on the US MkII Pineapple Grenade
Much more could be, and has been, written about the classic American hand grenade of WWII. But this brief article should arm the collector with enough knowledge to know what to look for when separating his or her ‘find’ into WWII or later vintage.
The MkII grenade emerged in 1918 and was modified again in 1942 as the MkIIA1. Its design encompasses a fragmentation body attached to a percussion-cap-and-time-fuse-delay detonation system atop a tapered neck. The ring held a safety pin in place prior to the grenade's activation. The time fuse delay ran for approximately five seconds after activation giving the soldier limited time to lob the device against an enemy. The body of the grenade was manufactured of iron with a pattern of protruding blocks which gave the grenade its unique appearance, aided handling, and increased fragmentation. The internal contents consisted of 2 ounces of TNT filling which would shatter the iron body causing massive fragmentation damage. Various fuses were used in the earliest and high explosive versions with the M6A4C fuse, with a 4 second delay, is found on the MkII High Explosive grenade, the M10 and 11 fuses on Low Explosive MkII’s . The pre-war grenades were painted yellow and with the onset of war most were over painted in olive drab, leaving a tell-tale yellow ring around the top of the body. At the end of WWII the MKII was replaced by the MK2 with the fuse top folding under the end cap as opposed to over it in the wartime configuration. In the 1950’s the Mk2 was phased out in favor of the round M26 grenade that saw extensive use in Vietnam.
The MkIIA1 hand grenade
Note the yellow paint ring at the top edge of the grenade body.
Two fuses found on wartime grenades.
The wartime 'folded over' cap
post war folded under