Projectile

A mass of metal discharged from a gun by the explosion of a charge of gunpowder or some high explosive, or by compressed air.

The projectiles used in the U. S. Navy for breech-loading cannon are armor-piercing shells, which are distinguished from the ordinary explosive shell by having thicker walls, not provided with a fuze, and having a smaller bursting charge. The bursting of these shells is insured by the heat generated by the blow.

The ordinary shell is of moderately thick walls, has a large bursting charge, and is furnished with a percussion fuze to cause the shell to explode on striking. These latter shells are for use against stone forts and earthworks, and vessels other than ironclads.

Shrapnel is furnished with a time fuze, has a small bursting charge, and is for use against boats and exposed masses of men on shore.