20-pdr. B. L. R., 15 and 13 cwt.;
12-pdr. B. L. R., 8 cwt.;
9-pdr. B. L. R., 6 cwt.;
6-pdr. B. L. R., 3 cwt.
Same construction as the 40-pdr., except that the coils are fewer.
Modified Breech-Loaders.
Although these guns are not yet introduced into service, they probably will be. The construction is the same in principle for the body of the gun as in the old breech-loaders, with slight modifications. The breech mechanism is almost identical with the French, the modifications being in the gas-check, which is of the general Broadwell type.
MUZZLE-LOADERS
(ORIGINAL).
Armstrong 10-inch Muzzle-Loader
(Original Construction).
These guns consist of a steel solid-ended tube, reinforced by a number of coils connected by hook-joints. The coils are of wrought-iron bars, rolled into hollow cylinders and the turns welded in order to give a circumferential direction to the grain. Over the breech and powder-chamber a forged breech-piece fits, the grain of the iron running longitudinally. The base of the A tube is supported by a solid wrought-iron piece screwing into the forged breech-piece. A narrow spiral gutter is cut around the A tube throughout its length, and carried out at the cascabel screw-thread. By means of this, in case that the steel tube gets cracked through, the leakage of gas gives warning by blowing out at the breech. Some of these guns (7-inch) have the shunt groove, and the later ones the Woolwich groove.
Modified.
The modified construction consists in abolishing the forged breech-piece, giving the steel tube a greater thickness over the powder-chamber, and decreasing the number of coils, whilst their thickness is increased individually. The guns are also given a greatly increased length of bore, and the powder-chamber is enlarged in diameter to permit the insertion of a heavier charge. Plain grooves.