Palliser shot and shell

Palliser shot is an early British armour-piercing artillery projectile, intended to pierce the armour protection of warships being developed in the second half of the 19th century.

[1] At the Battle of Angamos (8 October 1879) the Chilean ironclad warships fired twenty 250-pound Palliser gunshots against the Peruvian monitor Huáscar, with devastating results.

The base had a hollow pocket but was not filled with powder or explosive: the cavity was necessitated by difficulties in casting large solid projectiles without them cracking when they cooled, because the nose and base of the projectiles cooled at different rates, and in fact a larger cavity facilitated a better-quality casting.

In the shell the cavity was slightly larger than in the shot and was filled with gunpowder instead of being empty, to provide a small explosive effect after penetrating armour plating.

While these Palliser shells were effective against unhardened iron, British doctrine held that only shot (i.e. non-explosive projectiles) were suitable for penetrating the new hardened armour being developed in the 1880s; hence the gunpowder filling was discontinued.