Recoil

“ Recoil. In gunnery, is the retrograde motion impressed upon cannon by the discharge. The gas produced by the ignition of the charge in the bore, expanding with equal force in every direction, finds only two ways of escape (the muzzle and the vent) ; the pressure upon these points will therefore cease while it will be proportionally increased upon the parts directly opposite, that is, the bottom of the bore and that portion directly opposite the vent, producing in the first case the recoil, and in the other, indirectly, the dipping of the muzzle. ”

“ Mortars with iron beds immoveably fixed in the earth throw their shot to greater distances than guns which are affixed to carriages can do, and which, therefore, can recoil. This has been [320] incontestibly proved, both in large and small artillery. Having suspended a gun barrel, charged with a determinate quantity of shot, from the ceiling by two cords, so as to allow of its recoil, fire it point blank at a target, and mark the result accurately. ”

“ Recoil varies according to the position of the gun; when fired on the horizontal, the resistance to be overcome is the tendency of the projectile to fall to the earth, and its friction as it moves in a line parallel to the earth. ”

“ When the gun and trunnion-blocks rush back under the impulse of the recoil from firing, the water in the rear cylinders is forced out through escape-valves, which are held down by springs under a tension of 50 atmospheres. The recoil is thus checked in the space of 3 or 4 feet. If a larger charge is used the tension of the springs can be increased. The springs only come into play in resisting the desperate force of recoil. ”

“ In the first place recoil has been an important obstacle to contend with, ever since the invention of fire-arms, and the methods of lessening recoil have engaged the special attention of all inventors up to the present day; on this important point, indeed, very much depends. Gunnery is good only when recoil exists in a minimum degree. Force, whether it be that of the gentle “zephyr,” or of the mammoth steam-boiler which is capable of moving thousands of tons, can always be measured, and the friction of steam against the tube through which it passes can be measured also. ”

“ To avoid flinching and other movements of the head and body, caused by the recoil, begin your first practicing with a light powder-and-shot charge, say, about 2 dr. of bulk measure, or its equivalent in smokeless, and 7⁄8 oz. of No. 8 or 9 shot. There is no advantage in using a heavier charge, and the recoil of the gun will appear much greater in deliberate shooting at a target than is likely to be felt during the excitement incidental to shooting in the field. ”

“ I am satisfied that in all small guns, from their slight substance, recoil is communicated a great deal quicker than in larger ones; hence arises the well-known fact that in shooting you receive a knock nearly simultaneous with the explosion. The greater [69] and heavier the gun (even carry it up to General Miller’s gun of 84 cwt.) if the proportion which the shot bears to it be not too great, the less will be the velocity of recoil. ”

“ We also know that there is going to be a certain amount of recoil of the rifle. But if you will hold your sling as you have been instructed, if you will provide yourself with proper elbow and shoulder padding, the authors of this text assure you that you will experience no pain or harm from the recoil. It is their judgment that if you are healthy and can see and will go on the range with your jaws set to fire with anything like your gallery practice coolness, and calmness, you will qualify. Your greatest stumbling block will be your rapid fire. ”

“ The power for working the mechanism is obtained from the recoil, which, when the gun is fired, drives the barrel, together with the breech and the other moving parts, some two inches backwards, thus compressing the powerful recoil-spring which lies behind the breech, enclosed in the front part of the stock, and which, after the force of the recoil is spent, expands, and thus drives the barrel forward again into the firing position. ”

“ And as it also illustrates in a very direct way one of the most general laws of nature, while people often have very vague and erroneous ideas of its cause and operation, it deserves the reader’s attention. In gunnery it is called the recoil, and is familiar to anyone who has ever fired a pistol, fowling-piece, or rifle, in the kick backwards felt at the moment of the discharge. ”

“ Still, although I would never advocate doing this to any field gun (i.e., bringing a gun up short as it shakes the mounting too much) the fact remains that the range or shooting power of the gun may be varied with the recoil in a great degree, and that therefore what I mention about a system to check recoil uniformly and with certainty seems to me to be an important one with our Naval field guns. ”

“ The heavy recoil from a military rifle (which gives the bullet a speed of some thirty thousand feet a second) would shatter the recoil mechanism of a small pocket pistol, though the latter can quite safely operate under the slight recoil of its weak cartridge.
With a magazine rifle or revolver, the shooter uses just sufficient manual force to operate the mechanism, and even then pistols and rifles may get damaged by a clumsy man using too much force to wrench the weapon open or slam it shut. ”

“ The recoil and pulling the trigger throw back the right shoulder, which tend to increase the “derivation” to the right. If the twist were, then, from right to left, the drift, error from pulling, and from recoil, would tend to neutralize each other; the twist of the grooves should therefore be from right to left, instead of the present universal practice of from left to right.
On length of barrel.
The barrel of a gun may be looked upon as a machine in which force is generated for the propulsion of the bullet. ”

“ For example, if the weight of a gun be 160 times that of its ball 160/161 of the energy exerted by the powder in exploding will be employed in propelling the ball, and 1/161 in producing the recoil of the gun, provided the gun up to the instant of the ball’s quitting the muzzle meets with no resistance to its recoil except the friction of the ball. ”

“ When a rifle is fired the suddenly expanding gases push back against the breech of the gun with just as much pressure as they do against the bullet and this shows itself in the recoil or “kick” of the gun. Maxim utilized the kick of the gun to cock the gun, open the breech, eject the empty shell, take a fresh cartridge out of a magazine belt, insert it in the breech chamber, lock the breech and fire the gun. ”

“ The retrograde motion made by any piece of firearms on being discharged, which is a consequence of the rarefied air pressing on all sides, in order to expand itself with freedom. This term is generally applicable to firearms, especially to pieces of ordnance, which are always subject to a recoil, according to the sizes and the charge they contain, &c. Guns whose vents are a little forward in the chase, recoil most. To lessen the recoil of a gun the platforms are generally made sloping towards the embrasures of the battery. ”

“ A barrel, which recoils from being light, or from not being held firmly when fired, throws shot very weakly. So, on the other hand, barrels which have sufficient weight to break the recoil, or which are placed against something solid when fired, have their shooting power amazingly increased. ”

“ Mobility to a gun is given by the carriage on which it rides. The device which absorbs the recoil and restores the gun to position is called the recuperator (in the case of the hydropneumatic French design) or the recoil mechanism. ”

“ For if it recoil ever so little, the shooting force is as much weakened as if it recoiled twice as far.
“To increase that force, a steady fixed resistance is required. The velocity of the projectile depends on the force of the immediate impulse. Before a gun, suffered to recoil, could rebound from striking some solid substance in its recoil, the charge would be gone, and could, therefore, receive no additional impetus from that rebound. The truth of this fact may be illustrated by throwing a hand-ball against any loose body with sufficient force to displace it. ”

“ You may have stood behind a battery firing and noticed how one or two guns jump violently in recoil, while others would hardly disturb the proverbial glass of water on top of the wheel, although all guns of equal service. ”

“ I have tried this to a great extent, on a small scale, “with fowling-piece barrels,” and find that the greatest advantage arises from an additional inch of metal to the extreme end of the barrel, as the recoil is thereby lessened; while, on the contrary, by reducing [70] the exterior end of the breech, until it becomes of less thickness than the sides of the barrel, the recoil is doubled. Guns will some day be constructed as mortars are, with the axles, or trunnions, in rear of the tube and of the vent ”

“ Off at some convenient observation post, an observer gets the range of the target and telephones this range to the plotting-room, where a rapid calculation is made as to how much the gun should be elevated and swung to the right or the left.78 This calculation is then sent on to the gunners, who adjust the gun accordingly. When all is ready, the gun is raised by hydraulic pressure, and just as it rises above the parapet it is automatically fired. The recoil throws the gun back to its crouching position behind the breastworks. All that the enemy sees, if anything, is the flash of the discharge. ”

“ The Colt, Benet-Mercie, Hotchkiss and Lewis are in this class. They are all of the air-cooled type.
In the recoil operated guns, the barrel itself is forced to the rear by the "kick," as we commonly call it, and the force applied directly to the working parts, thus performing the same operations above described. ”

“ To mind the recoil of a gun seems pusillanimous, and few can believe, till assured by actual experiment, that it equals sixty or seventy pounds, and will crush the bones of the body if immovably fixed. Let the reader observe the next time that his gun is unwittingly left at half-cock, how far he will pull it out of aim, and how he will push against it, when attempting to discharge it at game. ”

“ An automatic machine gun in which the mechanism is worked by the recoil, assisted by the pressure of gases from the muzzle, which expand in a gas chamber against a disk attached to the end of the barrel, thus moving the latter to the rear with increased recoil, and against the front wall of the gas chamber, checking the recoil of the system. ”

“ The position of the gauge finger is the index as to whether or not the recoil is being properly absorbed.
[Pg 103]
The joints are not absolutely tight, the slight leakage which takes place during fire or even when gun is at rest is not important.
In normal firing conditions the recoil apparatus contains a slightly greater quantity of oil than absolutely necessary; this quantity is called the “reserve.” When the reserve is exhausted any loss is liable to reduce the quantity strictly necessary. The loss may prevent the gun from fully returning to battery when firing. ”

“ Whereas, with the shoulder gun, the finger which has let off the first lock flies back as the trigger is carried from it by recoil, and this sustained muscular action cannot be stopped by the will as quickly as the gun recoil is lessened by the shoulder. ”

“ The adjustment is made by the long rods attached near the breech and set at their lower ends to the position giving the intended angle to the raised gun. The varied and powerful strains to which the parts of this mechanism are subject, and which have had to be calculated and provided for, may be inferred from the enormous recoil energy of the gun, which under ordinary conditions amounts to no less than 730 foot-tons. The gun is provided with ordinary, and also with reflecting, sights, so that no one need be exposed to the enemy’s fire. ”

“ But the powerful weapon depicted in Fig. 102 is designed to be worked only by the manual effort of a few men. In this mounting the pressure of condensed air sustains the gun in the firing position; that pressure, acting upon the water in the recoil presses, having previously forced up their rams so as to turn into a nearly vertical position the strong brackets or beams on which the trunnions are supported. ”

“ Unless a gun can recoil, it will be smashed by the shock of the powder explosion.72 Usually, heavy springs are used to take up the shock, or cylinders filled with oil in which pistons slide. The pistons have small holes in them through which the oil is forced as the piston moves and this retards the gun in its recoil. ”

“ It is obvious that the recoil cannot come into action until a shot has been fired. A handle is therefore provided on the right-hand side outside the casing, by means of which the bolt forming the axis of the recoil and percussion arms may be turned so as to imitate the action of the recoil. This handle must be turned to bring the first cartridge into the chamber, but this having been done, the handle returns to its normal position, and need not be moved again. ”

“ Men who can understand the mechanism of a modern combined reaper and binder have no trouble learning the recoil apparatus of an eighteen-pounder gun, and for drivers one cannot find a better man than the farmer, for the man enlisting as such brings his own team with him and naturally will not neglect them. ”