Jam Tin Grenade

The  Double Cylinder, No 8 and No 9 hand grenades, also known as the "Jam Tin", were early designs used by the British Army in World War I.

The Double Cylinder was one of the many grenades designed for British use in the early part of the First World War in response to the failings of the No 1 grenade.

The grenade was an inner can of explosive with an outer can of metal fragments or ball bearings. The heavier pattern No 9 grenade contained more high explosive and more metal fragments.

The fuse was ignited by a friction device or a cigarette.

Initially when demand for grenades was at its greatest, engineers were encouraged to improvise their own grenades from the tins containing the soldier's ration of jam, hence the name. Incidents with the improvised form and the supply of superior grenades led to official withdrawal of the design.