Eureka Projectile.—Consists of a cast-iron body in one piece, with a brass sabot; the sabot is an annular disk intended to move on the frustum of a cone with an expanding cup in rear to take the grooves.
Ordnance Projectile.—Consists of a cast-iron body, with a sabot composed of an alloy of lead and tin, which is cast on the base of the projectile, and is held in position by undercuts and dovetails, the action of the charge being to force the sabot on the cast-iron body and to make it take the grooves.
Projectiles of special construction were formerly much used for particular purposes, as:
Bar-shot, which consisted of two hemispheres or spheres connected by a bar of iron either rigidly or in such a manner as to traverse its length; these were useful in cutting the masts and rigging of ships.
Chain-shot.—This differed from bar-shot only in the mode of connection, which was a chain instead of a bar.
Chain-ball.—To arrest the motion of rotation of an oblong projectile thrown under high angles, and with a moderate velocity, it has been proposed to attach a light body to its posterior portion by means of a cord, or chain, which will offer a resistance to the flight of the projectile, and cause it to move with its point foremost.
Nail-ball.—A round projectile, having a projecting pin to prevent it from turning in the bore of the piece.
Grooved Ball.—An oblong projectile, having spiral grooves cut along its base, by means of which the action of the charge produces rotation about the longer axis of the projectile. Sometimes these grooves are cut in the forward part of the projectile for the action of the air. Neither of these plans has succeeded in practice.
Bullets.—A bullet is a leaden projectile discharged from a musket, fowling-piece, pistol, or similar weapon.
Spherical Bullets.—When smooth-bore muskets alone were used the bullets were chiefly spherical in form and made by casting; at present, however, spherical bullets are manufactured by a compressing machine invented by Mr. George Napier. They are denominated by the number contained in a pound. In consequence of the great improvements that have been made of late in small-arms, the spherical bullet is now very little employed for military purposes, its use being chiefly confined to case-shot.