Gammon bomb

Overview

Designed by Capt. R.S. Gammon MC of the 1st Parachute Regiment, the Gammon bomb was developed as a replacement for the temperamental and highly dangerous "sticky bomb" grenade. It consisted of an elasticized stockinette bag made of dark coloured material, a metal cap, and an 'Allways fuze', the same fuze as found in the No. 69 grenade and No. 73 Grenade.

The Gammon bomb or grenade was an "improvised hand-thrown bomb used by the Home Guard, the Special Air Service and the Resistance, especially suitable for the destruction of aircraft or vehicles. An explosive charge was wrapped in fabric and sewn to an impact fuse that detonated on sharp contact".

Unlike conventional grenades, the Gammon bomb was flexible in the amount and type of munition that could be delivered to a target. For anti-personnel use, a small amount of plastic explosive (about half a stick), along with shrapnel-like projectiles if available, would be placed in the bag. However, against armoured fighting vehicles or other armoured targets, the bag could be completely filled up with explosives, making an unusually powerful grenade which could only be thrown safely from behind cover.

Using the Gammon bomb was very simple. After filling the stockinette bag with explosive, the screw-off cap was removed and discarded. Removing the screw-off cap revealed a stout linen tape wound around the circumference of the fuze. The linen tape had a curved lead weight on the end. While holding the lead weight in place with one finger (to prevent the linen tape from unwinding prematurely) the grenade was then thrown at the target. When the Gammon grenade was thrown, the weighted linen tape automatically unwrapped in flight, pulling out a retaining pin from the fuze mechanism. Removal of the retaining pin freed a heavy ball-bearing and striker inside the fuze, which was then held back from the percussion cap only by a weak creep spring. In this manner the Allways fuze became armed in flight. Impact with the target gave the heavy ball-bearing a sharp jolt - overcoming the weak resistance of the creep spring - that slammed the striker against the percussion cap. The percussion cap fired directly into the adjacent detonator, which in turn sent a violent shockwave into the main explosive filling contained inside the stockinette bag. Detonation of a Gammon grenade was instantaneous on impact with the target, i.e. there was no time-delay.

Gammon bombs were primarily issued to special forces such as paratroopers who were issued plastic explosive routinely. These units found the Gammon bomb to be particularly useful due to its small size and weight when unfilled, as well as its adaptability.

Gammon bombs were declared obsolete in the early 1950s, at which point all existing stocks were destroyed. Typically, any examples encountered today will be in the form of unexploded ordnance or inert examples held in museum collections.