Armstrong Gun.—Is so much like the Woolwich, which it preceded, that a separate description is unnecessary. See [Woolwich Gun].
Blakely Gun.—The most approved pattern of the gun invented by Capt. Blakely combines in its construction the principles of “initial tension” and “varying elasticity,” the object of which is to bring the strength of all the metal of the piece into simultaneous play to resist explosion. It is made of several tubes or barrels, the inner one of which is of low steel, having considerable but not quite enough elasticity. The next tube is made of high steel with less elasticity, and is shrunk on the barrel with just sufficient tension to compensate for the insufficient difference of elasticity between the two tubes. The outer cast jacket, to which the trunnions are attached, is the least elastic of all, and is put on with only the shrinkage by warming it over a fire. The steel tubes are cast hollow and hammered over steel mandrels under steam-hammers; by this process they are elongated, and at the same time the tenacity of the metal is increased, all the steel parts are annealed. Other combinations of iron and steel are used, except wrought iron, which is regarded as objectionable on account of its tendency to stretch permanently. Blakely guns were rifled with one-sided grooves, and are fired with expanding projectiles. This gun is no longer made under that name. As now made it is called the
Vavasseur Gun, and is manufactured by Messrs. J. Vavasseur & Co. of the London Ordnance-Works. It is made entirely of the best Sheffield cast steel, except the trunnions, which are wrought iron, and consists of an interior tube and outer tube and a number of hoops. The inner tube is forged from a solid ingot. It is rough bored and turned and then oil tempered. The outer tube and rings are cast hollow and hammered over steel mandrels. They are heated and shrunk on. Theoretically, it is difficult to pick a flaw in the construction of this gun. The rifling used is anomalous. It consists of three ribs instead of grooves projecting into the bore. The projectile has corresponding grooves. These guns have found quite a market in the South American republics.
Brooke Gun.—This gun was made after the plan of Capt. Brooke for the Confederate service; it resembles Parrott’s in shape and construction, except that the reinforcing band is made up of iron rings not welded together. The rifling is similar to that used in the Blakely guns.
Fraser Gun.—See [Woolwich Gun].
Gatling Gun.—See [Gatling Gun].
Krupp Gun.—See [Krupp Gun].
Lancaster Gun.—This gun is now little used; it was made of wrought iron. The bore was cut in a spiral form with an elliptical cross-section, and the projectile shaped to fit it, by which means a rotary motion was imparted.
Palliser Gun.—Maj. Palliser of the British service is the inventor of a system which has been successfully applied in England to utilize smooth-bore cast-iron guns by converting them into rifles. By his plan the gun is first bored to a cylinder or finely tapering cone, then lined with a tube of coiled wrought iron, the breech end of which is shrunk on; the exterior of the barrel has a uniform diameter throughout. The tube is double at this part to obtain the benefit of the tension and to enable any fracture of the inner layer to be made known without bursting the gun. The bottom of the barrel is closed by a wrought-iron cup screwed in. The tube is inserted into the gun from the muzzle without the application of heat. A small amount of play is allowed between the barrel and the cast-iron body; this disappears, or is much reduced by a “setting up charge,” which expands the barrel against the cast iron. The end of the barrel is made to bear accurately against the cast-iron breech. A collar screwed into the muzzle secures the tube in position, and prevents it from being thrust forward by the compression of the metal by repeated firing. In front of the trunnions a pin is screwed in through the cast iron, to resist the tendency of the tube to be turned by the bearing of the projectile in the grooves. On the exterior of that portion of the inner tube that is covered by the second tube is cut a spiral gas channel; this communicates with a tell-tale hole drilled through the cast-iron breech, by which gas can escape and announce the fracture of the inner tube. The venting and rifling are similar to those employed in the Woolwich guns. In the larger guns Maj. Palliser proposes to use two or more concentric tubes, in some the exterior one to be of steel. This system is being applied in the United States with the most promising results in the conversion of 10-inch Rodman guns into 8-inch rifles. The rifles thus obtained, though giving to a projectile a less muzzle velocity than does the 10-inch smooth-bore, has, on account of the increased weight of shot, greater penetrating power at all ranges, being doubled at some and trebled at others. Its accuracy is three times greater, and the capacity of its shell twice that of the original gun.
Parsons Gun.—The system upon which Mr. Parsons makes his guns is similar to that of Maj. Palliser. (See [Palliser Gun].) It depends upon the principle of varying elasticities, and is based upon the fact that wrought iron may be stretched three times as much as cast iron, and will offer three and a half to six times the resistance within the limit of its elasticity. These well-known gun constructions, known as converting systems, both consist in lining a cast-iron case with a wrought-iron or steel tube. In the Palliser or English method the tube is inserted from the muzzle. In the Parsons or American method, through the breech. In both nearly the whole of the longitudinal strain is transferred to the cast-iron case. Both systems were first perfected in England. Col. Crispin (U. S. Ordnance Corps) deserves the credit of introducing them into the U. S. service in constructing the new experimental rifles. The Parsons system is better adapted to constructing breech-loaders.