designed to pierce armour, esp. (in later use, of a shell, etc.) designed to penetrate the armour-plating of a ship, tank, etc., before exploding.

Of a ball, shell, etc. That has been cut with grooves. Obsolete. rare.

characterized by, involving, or producing a high speed (cf. high-speed, adj.); spec. (of a gun) capable of discharging a projectile with great force…

attributive. Adapted for guns having a smooth bore.

Of a projectile: smaller in calibre than the gun from which it is fired, and typically discharged from a secondary tube set inside the main…

Military. Designating a missile which makes a whistling sound in flight, or a gun from which such missiles are fired. Frequently in the nicknames of…

= full-metal-jacket, adj.

Designating a bullet with a metal (usually copper or other alloy) casing which fully surrounds the lead or other core material; abbreviated FMJ.

Designating a type of small high-velocity shell distinguished by the sound of its flight. Obsolete.