Chapter three
A bayonet and its influence on the accuracy of a three-line rifle.
Having completed our research on why the three-line was fired only with a bayonet attached, let's move on to the next - did the bayonet affect rifle shooting, and if it did, then how.
Let's answer the first part of the question right away - influenced. A load weighing half a kilogram, fixed at the end of the barrel, cannot but influence the battle of the weapon. Therefore, already in the "Manual for shooting training" 1884 contains an indication of the need to take this factor into account.
In order to understand how the presence of a bayonet affects the fight of a rifle, you will have to make a short historical excursion again and turn to the Soviet shooting school. One of the most powerful bullet shooting schools has developed in the USSR. Systematic scientific and methodological work was carried out and special methodological manuals were prepared, developed by such luminaries as M. A. Itkis, L. M. Weinstein, A. A. Yuriev and many others.
We will turn to one of these manuals, or rather a book.
A. A. Yuriev, Shooting sport. Moscow, FiS, 1962 (Second edition).
The question may arise: what does sports shooting have to do with the Mosin rifle? The answer is simple. In those years, an army service rifle of the Mosin system, model 1891/30, caliber 7, 62 mm was used in shooting sports to perform the following exercises:
“Standard”, that is, shooting from three positions - prone, kneeling and standing - at 300 m at target No. 3;
high-speed prone shooting 5 + 5 and 10 + 10 at 300 m at chest target No. 9;
duel shooting - a team exercise with a sprint and prone shooting at 300 m at target No. 6;
shooting with a telescopic sight at a position of 600 m at target No. 3.
And one more nuance. The rules of the competition prohibited to make any changes to the design of the rifle. Its weight should not exceed 4.5 kg, total length with a bayonet - no more than 166 cm, without a bayonet - 123 cm. Thus, a standard army rifle was used.
The book examines in detail the many factors and specific conditions that accompany and affect high-precision shooting.
First, a little theory.
During the combustion of the charge, the expanding powder gases are pressed with equal force on the entire surface of the volume they occupy. The pressure that the gases produce on the walls of the bore causes them to expand elastic; the pressure of gases on the bottom of the bullet makes it move quickly along the bore; the pressure on the bottom of the sleeve, and through it on the bolt, is transmitted to the entire weapon and forces it to move back in the direction opposite to the movement of the bullet. We can say that when fired, the forces of the powder gases seem to throw the weapon and the bullet in different directions. The movement of the weapon back when fired is called the recoil of the weapon.
The force of the pressure of the propellant gases, causing recoil, acts along the axis of the bore in the direction opposite to the flight of the bullet. The recoil of the rifle is perceived by the shooter's shoulder at a point below the axis of the bore. Shoulder resistance to recoil is the reaction force that is directed in the opposite direction to recoil and is equal to it. A pair of forces is formed, which forces the rifle to rotate the muzzle upward during the shot (Fig. 100).
Let no one be surprised by the number of the picture. Figures are numbered the same as in the book for convenience.
From the above, it can be seen that the weapon, when fired, under the influence of the recoil and reaction of the shooter's shoulder (or hand), not only moves back, but also rotates with the muzzle upward (Fig. 102). In this case, the tossing of the barrel upward begins even while the bullet is in the barrel bore.
Consequently, the axis of the barrel bore at the time of the shot is displaced by a certain angle. The angle formed by the direction of the bore axis before the shot and at the moment the bullet leaves the bore is called the departure angle (Fig. 103).
The formation of the departure angle is a very complex phenomenon and depends not only on the recoil of the weapon, but also on the vibration of the barrel. If you hit any rod made of an elastic material, then it begins to vibrate (vibrate). The same thing happens with the barrel of the rifle. With the combustion of the charge and the resulting impact of the powder gases, the barrel begins to vibrate like a tightly stretched string. The thinner the barrel, the more it vibrates, the more massive the barrel, as, for example, in target rifles, the less vibration will be. The phenomenon of vibration consists in the fact that all points of the trunk begin to vibrate somewhat relative to their normal normal position. At the same time, as has been established empirically, the range of oscillation of points located in different places along the length of the trunk is different; it turns out that there are points on the trunk that do not vibrate at all, the so-called nodal points (Fig. 105). Together with other sections of the barrel, the muzzle also vibrates (vibrates). Due to the fact that the wave-like vibrations of the barrel begin before the bullet flies out of it, the final direction of the bullet depends on which phase of the barrel muzzle oscillation coincides with the moment of its departure.
From this it becomes quite obvious that the departure angle depends to a large extent on the vibration of the barrel. If, during its oscillation, the muzzle part of it at the moment of bullet departure is directed higher than before the shot, then the departure angle will be positive, if lower, then negative. As a matter of fact, the shooter is completely indifferent to what angle of departure is obtained when shooting - positive or negative. It is important that the take-off angle is relatively constant and there is no bullet spread. To achieve uniformity in the angles of departure, it is necessary to debug the weapon so that the barrel can experience vibration (vibration) always uniformly.
When firing with a bayonet, due to a change in the nature of the vibration of the barrel, a negative departure angle is formed, and without a bayonet, a positive one.
In addition, due to the attachment of the bayonet to the barrel on the right, the rifle's center of gravity also shifts to the right; during the shot, a pair of forces is formed, which rotates the rifle in the direction opposite to the bayonet abutment (Fig. 106). Therefore, if you start shooting without a bayonet from a rifle, then the middle point of impact (STP) will change dramatically. Given the great influence of the bayonet on the formation of the departure angle and the movement of the STP, you must always make sure that it does not swing and is tightly adjacent to the barrel.
The bent bayonet also affects the change in STP. If the bayonet is bent to the right, then the STP will move to the right; if it is bent up, then the STP will move down. Therefore, the shooter must carefully protect the bayonet from bending. Thus, the influence of a bayonet on the movement of the midpoint of impact was known long before the "3-line rifle of the 1891 model of the year" was created.
Let's remember this moment and move on to derivation.
