[3] A machine-gun of the artillery or volley type, called the “Requa battery,” which had its barrels disposed fan-wise, was also used in the Civil War.
[4] The U.S. pattern Gatling hardly differed except in details from the model, above described, of twenty years earlier. The drum had been set horizontally instead of vertically and improved in details, and a “gravity feed,” a tall vertical charger, was also used. The barrels were surrounded with a light casing. Tests made of the improved Gatling showed that the use of only one barrel at a time prevented overheating. On one trial 63,000 rounds were fired without a jam, and without stopping to clean the barrels. Smokeless powder and the modern cartridge case were of course used.
[5] The following particulars may be given of the 2-barrelled Gardner and 3-barrelled Nordenfeldt (land service) converted to take the .303 cartridge: Weight, 92 and 110 ℔ respectively; parapet mounting in each case 168 ℔; rate of fire of Gardner about 250 rounds per minute, of the Nordenfeldt about 350. A few of these guns are still used in fortresses and coast defences.
[6] Modern improvements in mechanical details are only slight, as may be found by reference to the official handbooks of the gun, editions of 1903 and 1907.
[7] At San-de-pu 1905 the Japanese machine-guns (Hotchkiss) sustained damage averaging, 1 extractor broken per gun, 1 jam in every 300 rounds. It should be mentioned, however, that the machine-gun companies were only formed shortly before the battle.
[8] In field operations only. For siege warfare see [Fortification and Siegecraft].
[9]For practical purposes in the field, the “effective” beaten zone, containing 75% of the bullets, is the basis of fire direction both for the machine-gun and the rifle. The depths of these “effective” zones are on an average:—
| At | 500 yds. | 1,000 yds. | 1,500 yds. | 2,000 yds. | |
| S.L.E. Rifle | 220 yds. | 120 yds. | 100 yds. | — | |
| Maxim Gun | 150 yds. | 70 yds. | 60 yds. | 50 yds. |
[10] “Combined sights” implies firing with the sights set for two different ranges, the usual difference being 50 yds. With grouped machine guns, “progressive fire” with elevations increasing by 25 yds. is used. This artificially disperses the fire, and therefore lessens the chance of losing the target through ranging errors. One ingenious inventor has produced a two-barrelled automatic, in which the barrels are permanently set to give combined elevations. The British memorandum of August 1909 seems to regard the facility of employing combined sights as the principal advantage of the battery over the section.
[11] The use of single guns facilitates concealment, but this is outweighed by the objection that when a jam or other breakdown occurs the fire ceases altogether. The use of guns in pairs not only obviates this, but admits of each gun in turn ceasing fire to economize ammunition, to cool down, &c. This is the old artillery principle—“one gun is no gun.”