Mortar

Short cannon, intended for curved fire, generally at an angle of elevation of 45°. The old smooth-bore mortars be fired with great initial velocities and give great ranges. The rifling gives them great accuracy and increases their efficiency in po ible destructive effect against the enemy's ve els. In U. S. service the latest designed seacoast mortar is the 12-inch steel, weight 29,100 lbs., firing a 1,000 lb. projectile with a charge of 105 lbs. powder, giving a muzzle velocity of 1,140 ft. sec. and muzzle energy of 7,207 ft. tons.