Explosive Shot

Lore & Background

The mine shell relies on inflicting damage primarily through the blast (pressure wave) alone, rather than the higher fragmentation but less blast provided by standard high-explosive shells. The specific effect, in German called Minenwirkung, in Swedish minverkan, lit. 'mine action', is defined by the Swedish Armed Forces as 'the pressure action from an encased explosive charge'. The effect is desirable when attacking non-reinforced and non-armoured targets such as brittle brick or concrete, and aircraft skin, as these are relatively easy to penetrate and do not need to be attacked by heavy, hard projectiles, but are tough enough to maintain their structure despite being pierced by shellfire and fragmentation. The larger explosions generated by mine shells are more efficient at inflicting damage on such targets than the greater kinetic impact but smaller detonations delivered by conventional rounds.

Reader's Guide

To achieve the mine shell effect, shells have very thin shell walls, leaving more room for explosive filler, at the cost of generating lighter and less damaging shrapnel. Shells for use against thicker targets, such as brick or concrete walls, often use a delayed action fuze allowing them to penetrate a wall before exploding, forcing larger pieces of the targets to break loose. An additional advantage is that, as explosives are less dense than metal, the projectiles weigh less, giving them higher muzzle velocity than heavier shells and generating less recoil. Less desirably, the lighter shell has less momentum, and consequently shorter range. The lower recoil also makes them unsuitable to be fired from a gun with a recoil operated or advanced primer ignition mechanism suitable for heavier standard shells. This forced Germany during World War II to develop a special variant of the 20 mm MG FF cannon to fire mine shells, subsequently becoming the 'MG FF/M' (for Minengeschoß). Mine shells are often made longer than other shells of the same caliber, to increase both the weight and the explosive payload.

Did You Know?

• The word 'mine' in 'mine shell' originally referred to mining tunnels used in siege warfare to collapse fortifications, not land mines or naval mines.
• The 20 mm mine shells used in the MG FF/M cannon had a 17 g HE filling, compared to only 4.5–6.5 g in the original MG-FF round.
• The German R4M air-to-air rocket's name stood for 'Rakete, 4 Kg, Minenkopf' (Rocket, 4 kg, Mine-head).
• The formal British military term for mine munition is 'High Capacity' (HC), with mine shells called 'High Capacity High-Explosive' (HCHE).