Explanation of a Spigot Mortar Position


Typical Spigot Mortar Position

The Spigot Mortar or "Blacker Bombard" was invented by Lieutenant-Colonel Blacker with the aim of providing cheap and easily produced weapons after most of the British Armys heavy equipment had been lost at Dunkirk.

gunKnown as a spigot this design differs from more conventional efforts by dispensing completely with a barrel of any kind, instead using a projectile with a hollow tail unit. This hollow tail contained a percussion charge, which is detonated by the impact of a steel rod, which is driven into the tail

The explosion of the charge propels the mortar towards its target

The mortar is supported on a simple steel pin or a tripod.


In its static defence role, the mortar was mounted on a steel pin set into a substantial base of reinforced concrete. This was in turn set:-

(a) at ground level protected by concrete re-inforced side walls.
Next to the plinth by the wall on the left, are the remains of two ammunition alcoves side by side.
(b) a camouflaged weapons pit to offer some protection to the three man gun crew.
(see B & W picture above)

The weapon fired a 20lb fin-stabilized anti-tank bomb warhead containing a high explosive charge using black powder as a propellant. The weapon had the drawback of when the warhead hit its target, the fins had a nasty habit of flying backwards along the original trajectory with the resulting danger of injury to the firing crew. The "Bombard" had an effective range with the anti-tank bomb of around 100-150 yards, so the firing crew was expected to wait until any tanks were at close range. It was also capable of firing a 14 lb anti-personnel bomb with a maximum range of around 500 yards. They were fairly accurate and effective at short range. A portable mount was also available, but weighed around 350lb and took 3 men to move it.

How it worked
A large spring was cocked by unlatching the shoulder pad, standing on it, and pulling the weapon up so that the spigot and spring were latched in the firing position. This was only done for the first cocking before firing. The body was then slid back to the shoulder pad and latched.

A bomb was then placed in the tray at the front of the weapon and it was ready to fire. On pulling the trigger the spigot was released from the spring. It entered the rear of the bomb where it ignited an explosive charge, which propelled the bomb along the spigot and out of the weapon. The same explosion repelled the spigot back into the spring re-cocking the weapon. All that was needed was another bomb added to the tray.

The weapon was rejected by the regular army but saw service with Home Guard and airfield protection units from 1941-1944. It was very effective against tanks, if you had the nerve waiting for them to be within the 100yd firing range.