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. Against armored fighting vehicles or other large targets, the bag could be filled completely with explosive. In this manner it was possible to make an unusually powerful grenade that could only be thrown safely from behind cover.
Using the Gammon bomb was very simple. After filling the stockingette 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. Whilst 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 were then held back from the percussion cap only by a weak creep spring. In this manner the -fuze was armed in flight. The grenade exploded when impact with the target gave the heavy ball-bearing a sharp jolt, overcoming the weak resistance of the creep spring to slam the striker against the percussion cap. Detonation of a gammon grenade was instantaneous on impact with the target.
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 their small size and weight when unfilled, as well as their 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.