Page images

at four inches from the breech end as in other guns at that part itself. This will be better understood by referring to fig. 42, which shows the chamber opened ready for the reception of the cartridge, and which will then give an idea of the part where the real barrel begins, w ch is marked a in the cut. There must be enough strength behind this to resist the backward action of the explosion, but the metal need not be left of full thickness for this purpose, as the area upon which the force is exerted is only that of the diameter of the bore. The strain is not entirely upon the bolt-hole b, which keeps the breech-plug up against the barrel, for the base of the lock-cylinder is wedged up, and transmits the recoil to the stock. There is nothing very peculiar in other respects in Mr. Needham's barrels, which are relieved before in the usual manner, and also opened behind to an extent which will allow of the ready insertion of the cartridge. By this arrangement it will at once be seen that when the breech-plug c is in its place, the chamber for the reception of the powder is similar to that of the French gun already described, and that there is no conical chamber like that in the breech of the percussion gun. In this respect, therefore, the two guns are alike; and if there is any virtue in the Manton, Wilkinson, or other form of breech chamber, neither can claim it, and both in this matter stand on the same footing But when the mode of closing the breech comes to be examined, it will be seen that this is more complete in Mr. Needham's than in the French gun in one particular, while it is less so in another, the balance of advantage and disadvantage being somewhat difficult to strike.

The breech-plug (tig. 41 a) should be considered as quite independent of the lock, though it also contains that important part within it, and has a small hole in its face to allow of the needle being driven through it into the cartridge. In this hole is the element of weakness, for through it, however well the needle fits, will be a small escape of gas, consequent upon the explosion. Independently of this the plug consists of two parts, each of which serves a double office—firstly, of closing the breech, and secondly, of acting on or containing the lock. In reference to the breech, this plug may be described as consisting of two portions-an anterior (a, fig.

41), which is projected into the barrel, and a posterior part, which forces it forward as the screw is turned by the lever. The part a terminates in a short cone which fits accurately into the barrel, and with the aid of the wad at the base of the cartridge closely fills the aperture and prevents the escape of gas between the two circumferences. But the centre of this, where it is pierced by the needle, as shown in fig. 40, is not so completely free from escape, and to prevent the gas from passing backwards into the lock, a hole is drilled as there indicated. These two divisions are each tapped, the anterior one being constructed with a female screw, and the posterior showing a male screw of a strong formation (fig. 41 b). The effect of this is so obvious as scarcely to require the explanation that, when one is fixed as it is by the bolt (fig. 42 b), and the other is turned by the lever, the total length is increased or diminished as the case may be. The pitch of the screw is so slight that no force which can be applied by the explosion will drive the plug back; and its lever, when closed, being also held in its place by a spring catch (see fig. 42), a sufficient resistance is doubly secured.

The lock has been already described as being contained within the breech-plug, and therefore its actions must be of small size and of simple construction. Independently of the plug which contains them, it may be said to consist of four actions:-1st, the needle (fig. 43); 2nd, the mainspring (fig. 44); 3rdly, the screw cam (fig. 45), which drives the needle back; and 4thly, the scear (fig. 46 a c), which holds it ready for the trigger. There is also a bolt (fig. 47), which is intended to act as a substitute for the “half-cock” of the ordinary lock, and which

Fig 43. really is quite as efficient in preventing danger. The needle (fig. 43) consists of a three parts—a centre and

b two extremities. The

THE NEEDLE. (HALF size.) front is a mere needle a about a line in diameter, and terminating in a sharp cutting point, which readily pierces the paper base of the cartridge. The middle receives this needle, and consists of two flat shoulders or wings standing out from a strong pillar (see b),


and sliding in corresponding traverses, within the posterior half of the breech-plug. These wings answer a treble purpose—firstly, they receive the pressure of the spring from behind; secondly, they maintain a steady sliding action; and thirdly, they are capable of receiving the pressure of the cam (fig. 45), which is a double inclined plane fixed within the plug, and which, when turned round, thrusts the whole needle backwards. When this is done its posterior extremity being notched, drops upon the scear and is held back after the cam is restored to its orignal position. In addition to the notch for the scear (see fig. 43 c), there are sometimes two others at the side (at d) for the reception of the bolt, but in those lately made by Mr. Needham the stop is effected by the bolt dropping into the scear instead of the needle, as will be presently explained. The mainspring

[merged small][merged small][ocr errors][merged small][merged small][merged small][merged small]

(fig. 44) is of very simple form, being merely a spiral spring dropped into the posterior half of the plug and pressing against the wings of the needle. Next comes the screw cam (tig. 45), which is fixed within the plug, and is perforated by à hole for the needle; two inclined planes are so arranged that as the plug is turned round they press upon the wings in the needle already described, and push it back till it catches the scear. As a matter of course these cams are

reversed on the two sides Fig. 46. of the gun, since the lever

in one case is turned to the right and in the other to the left. The scear and spring, with the

trigger (fig. 46), complete SCEAR-SPRING, SCEAR, AND

the actions in this lock, TRIGGER. (HALF SIZE.)

with the exception of the



bolt. The scear a is much smaller than in the common lock, and is a catch of the most simple description pressed down into its place by the spring b, and working upon the centre c. As in the old lock it has a projecting arm which catches the trigger, but since it must be pushed down instead of up, the trigger requires to be of a somewhat different construction in order to accomplish the liberation of the needle. This is effected by carrying forward a lever in the trigger (see fig. 46, in which this is represented at d), ready to depress the arm of the scear below it when the trigger is pulled. From the want of room to play, and the consequent small size of scear, there is not the freedom of action to be found in the old locks, which will be missed by those who are fond of handling them and making them “speak.” This, however, is a mere fancy; and so long as the lock does its duty with safety and efficiency, it is little consequence whether it is musical or not. Lastly, the bolt (fig. 47) is to be described as follows:

It is made in the form of a short screw, terminating within in a sharp wedge, and without

Fig 47 in a lever about an inch in length. The bolt is inserted in its place by screwing it in till it

(HALF SIZE.) reaches its bearings; when home, a little projecting knob traverses a smooth surface, slightly rounded, on the outside of the lock, so that when the lever is either raised or depressed, it is held firmly in that position. On comparing the shape of the wedge at the end of the screw with the notches in the needle, when the old plan of stop is adopted, it will at once be seen that when the former is raised, this wedge lies in the axis of the needle, and allows the longitudinal notch to traverse freely upon it, while on depressing it after the needle is caught by the scear, this same wedge acts as a secure catch upon the third notch of the needle, and prevents its being liberated on the pulling of the trigger. When the scear is bolted instead of the needle, the catch merely drops into a notch in it, but in either case, when these parts are in good order, and the bolt is lowered so as to show the word BOLTED, as in fig. 39, the lock is as safe as need be, and I believe that there is far less danger than in the ordinary lock at half-cock, because there is no chance of Mr.



Needham's bolt being raised in passing through a hedge, which may happen to the striker of any of the locks constructed on the ordinary pattern. After the above description, it will at once be apparent that in the act of opening the breech, the lock is cocked, and that before closing it, the bolt ought to be lowered so as to show the word BOLTED, or else the gun is in the same dangerous state as it would be if on full cock in the ordinary kinds of gun. This precaution is of great importance to the safety of the sportsman who uses Mr. Needham's invention, and as the bolt can be raised by the left hand at the moment of taking aim, there is never any necessity for carrying this gun cocked, or I should rather say unbolted.

The cartridge-case employed is a much cheaper and more simple affair than that used for the Lefaucheaux gun, being

[merged small][graphic]

SECTION OF LOADED CARTRIDGE. (FULL SIZE.) composed, however, of the same elementary parts, with the exception of the brass pin, whose office is here performed by the needle. Every part, however, is modified, and there is not nearly so much difficulty in constructing it. Besides this, the case is not withdrawn after being used, so that there is not the same necessity for its fitting the chamber easily, as in the French gun. The most important part is the arrangement of the wad and cap, which must be examined attentively, in order to comprehend their offices (see figs. 48 and 49), in which these parts are represented in

Ftg 49


« PreviousContinue »