page_title: Naval artillery
section_title: Armour-piercing shot
hierarchical_section_title: Naval artillery / Industrial era / Armour-piercing shot
caption_attribution_description: Diagram of Mk VI Palliser shot for British RML 7 inch 7 ton gun.
context_page_description: Naval artillery is artillery mounted on a warship, originally used only for naval warfare, later also for shore bombardment and for anti-aircraft use. The term generally refers to tube-launched projectile-firing weapons and excludes self-propelled projectiles like torpedoes, rockets, and missiles and those simply dropped overboard like depth charges and naval mines.
context_section_description: The late 1850s saw the development of the ironclad warship, which carried wrought iron armor of considerable thickness. This armor was practically immune to both the round cast-iron cannonballs then in use and to the recently developed explosive shell.
  The first solution to this problem was effected by Major Sir W. Palliser. His Palliser shot, approved in 1867, was made of cast iron, the head being chilled in casting to harden it, using composite molds with a metal, water cooled portion for the head. At times there were defects that led to cracking in the projectiles but these were overcome with time. Bronze studs were installed into the outside of the projectile so as to engage the rifling grooves in the gun barrel. 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 their 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.
  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. It was the first time that such piercing shells were used in actual combat.
  These chilled iron shots proved very effective against wrought iron armor, but were not serviceable against compound and steel armor, which was first introduced in the 1880s. A new departure therefore had to be made, and forged steel rounds with points hardened by water took the place of the Palliser shot. At first, these forged-steel rounds were made of ordinary carbon steel, but as armor improved in quality, the projectiles followed suit.
  During the 1890s and subsequently, cemented steel armor became commonplace, initially only on the thicker armor of warships. To combat this, the projectile was formed of steel—forged or cast—containing both nickel and chromium. Another change was the introduction of a soft metal cap over the point of the shell – so called "Makarov tips" invented by Russian admiral Stepan Makarov. This "cap" increased penetration by cushioning some of the impact shock and preventing the armor-piercing point from being damaged before it struck the armor face, or the body of the shell from shattering. It could also help penetration from an oblique angle by keeping the point from deflecting away from the armor face. (See: APCBC ammunition)
  Increased armor penetration became possible when projectile velocities of 800 m/s (2,600 ft/s) were obtained as smokeless powder propellants replaced gunpowder about 1900.
caption: Palliser shot, the first armour-piercing shot for RML 7 inch gun, 1877.
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