Having by experiment developed the best drill, so far as the officer in charge of it is able to judge, the men should be exercised at their duties until their movements have become nearly me chanical. The stage is now reached at which target practice must be begun. In the United States Navy the gun-firers for the principal guns nearly all receive a preliminary training in the gunnery ships, and hold the ratings of gun cap tain (chief, or first or second class). In the United States service the expenditure of time and ammunition for target practice is greater than in any foreign navy. There are seven prac tices a year in which full-calibre ammunition is used; six sea practices in which no attempt is made to obtain an exact record of the firing be yond what is necessary for purposes of immediate instruction and the information of the gun-firer, so that he can correct his errors; and one record practice in which the exact records of the firing are sought, in order to furnish the Navy Depart ment with information as to the efficiency of the men who operate the guns. The expenditure of ammunition per gun per year is fixed as follows: 10, 12, and 13 inch guns, 12 rounds; 8 inch, 18 rounds; 7-inch, none yet in service; 4, 4.7, 5, and 6 inch guns, 24 rounds; 3 inch, 36 rounds; 3-inch field gun, 18 rounds; 1, 3, and 6 pounders, 72 rounds; Gatlings and Colt automatic guns, 1100 rounds. In order to give a greater amount of practice than is afforded by any reasonable expenditure of the ordinary ammunition, the sub calibre principle is used. This consists of a small barrel or gun securely clamped to the outside of a large gun, or inserted in disks and then placed in the inside of the gun, where it is firmly held in position. The gun-firer trains and ele vates the large gun, using its sights, but setting the elevation in accordance with a table which adapts thernsto the various ranges of the small piece. So far as the training of the gun-firer is
concerned, this is almost as good as firing large charges, and the reduction in expense is 90 to 99 per cent. The sub-calibre practices are held about once a month, and the amount of ammunition which may be expended is left to the discretion of the commanding officer of the ship. The targets used are made of canvas, supported by a frame work or pole; the common one, supported by a pole, is triangular; but a rectangular one will probably be used in future for certain record practices. In addition to target practice, gun firers are practiced at aiming with a device which records the direction of the sights when the firing button is pressed, and which keeps the little tar get, which is at the muzzle of the gun, in motion in a manner to simulate the apparent movement of a real target past the sights when the ship rolls. For training on shore, an oscillating or rolling platform has been designed which gives the gun motion similar to that which it has on a rolling ship.
For further information on the subject, con sult: (Hermon. Accuracy asul Probability of Fire (Baltimore, 188S) ; id., Interior Ballistics (Bal timore. 1894) ; Ingersoll, Text-Book of Ordnance and Gunnery (Annapolis, 1899) ; id., Exterior Ballistics (Baltimore, 1893) ; Bruff, Text-Book of Ordnance and Gunnery (New York, 1896) ; Proceedings of United States Naval Institute (Annapolis, current) ; Journal of the United States Artillery (Fort Munroe, Va., current) ; Annual Reports of the Office of Naval Intelligence, particularly that for 1899 (Washington). See AR: TILLERY ; BALLISTICS; COAST ARTILLERY; Ex PLOSIVES; FIELD ARTILLERY; GUNS, NAVAL; GUNPOWDER; ORDNANCE; PROJECTILES; etc.