Weapon recoil momentum. The recoil force of firearms depending on the caliber
In this article, I deliberately refuse any matan, abstruse terms and other grandiloquent words. That is why the text contains various inaccuracies and formal errors. But there will be no vectors, derivatives, integrals and other boring science.
In theory, at school we learned Newton's laws and, at the same time, the conclusions from them. Remember action equals reaction? m1a1=m2a2 (minuses are omitted), where m is the mass, and ˜ is the acceleration. This implies the law of conservation of momentum (momentum). Recall what an impulse is: a vector physical quantity, which is a measure of the mechanical motion of a body.
In classical mechanics, the momentum of a body is equal to the product of the mass m of this body and its speed v, the direction of the momentum coincides with the direction of the velocity vector. p=mv. And the law looks like this: In a closed system, the vector sum of the impulses of all bodies included in the system remains constant for any interactions of the bodies of this system with each other. This is one of the interpretations.
And now we will remember the laws of jet propulsion. They directly follow the law of conservation of momentum: MrocketsVrockets=MgasVgas, where Mrockets, Vrockets are the mass and velocity of the rocket, and Mgas, Vgas are the mass and velocity of gases emanating from the rocket. So we get an impulse, we consider the force of interaction, the acceleration of the rocket. For some reason, “great specialists” do not appear who declare with aplomb that the speed of a rocket should be calculated not through the momentum “MgasVgas” of reactive gases or the repulsive force, but through their energy (MgasVgas² / 2). Well, I have not met such "specialists".
But there are a lot of "specialists" who judge the recoil of a firearm by the muzzle energy of a bullet. They often find that SUDDENLY the recoil energy of the weapon is equal to the muzzle energy of the bullet. Why the weapon does not kill the shooter is not clear.
Consider a spherical vacuum example. So, in a vacuum under conditions of weightlessness, there is a motionless (yes, in the accepted inertial coordinate system, blah, blah, blah - there will be no more matan) “spherical gun” TT with a mass of 0.91 kg. And now he shoots a “spherical bullet” with a mass of 0.0055 kg (5.5 g) at a speed of 480 m / s. For simplicity, we will assume that this is an elastic interaction. We neglect all kinds of rotations of the bullet and the rest.
So the "spherical TT" threw a spherical bullet away from itself. According to the law of conservation of momentum MstVst = MbulletsVbullets. From: Vpis= MbulletsVbullets/Mpis=0.055*480/.091=2.9m/s. That is, after expansion, the “spherical TT” will move at a speed of only 2.9 m / s.
Let's take and calculate their energies after the expansion:
Epules \u003d 0.0055 * 480² / 2 \u003d 633.6 J.
Epist \u003d 0.91 * 2.9² / 2 \u003d 3.82 J.
Oh my God! How so!! The pistol has 165 times less energy!!! Maybe that's why, when fired, the arrow does not kill with a flying pistol?
But let me, you say, but what about the law of conservation of energy? And where does it come from, this energy? Isn't it the conversion of the thermal energy of the burning powder gases into mechanical energy bullets? But in fact, a firearm is an inertial internal combustion engine. It just moves the bullet for the most part. And his efficiency is usually very so-so.
Let's get to the point. Any, absolutely any source describing recoil formulaically operates not with the energy of a bullet, but with its momentum! In order to make sure of this, not much is enough: drive the queries “weapon recoil”, “weapon recoil momentum”, “weapon recoil force”, “weapon recoil energy” into the search engine. Wherever there are formulas (including descriptive ones), they operate not with the muzzle energy of the bullet, but with its momentum. Try to refute. Formally.
Everything would be fine, but except for the bullet, the weapons are repelled by the high-temperature powder gases emanating from the barrel. It’s just a reactive force, the right word.
Therefore, the total momentum of the weapon flying back is considered in the form:
WeaponsVweapons=MbulletsVbullets+MgasesVgases.
Naturally, the recoil momentum will be greater than the momentum of the bullet. But it is extremely difficult to assess the effect of powder gases. Their speed is very high (up to 2000 m / s), but the mass is small and the process of departure from the barrel is difficult to take into account. There are a number of empirical formulas for calculating the recoil momentum of a cartridge. Yes, it is the recoil momentum of the cartridge. It consists of the recoil momentum of the bullet and the recoil momentum of the propellant gases. I use Blagonravov's EMNIP formula, which is common in the Soviet school:
Io=mc*(1+(mp/mc)*(1275/V))*V, where:
M - the mass of the weapon
mc - bullet mass
mp - mass of gunpowder
V - bullet speed
Empirical kit 1275 walks a little depending on the speed of the bullet, but that's not the point. Read: Babak F.K. "Fundamentals of small arms" (Article 43) or Kirillov V.M., Sabelnikov V.M. Small arms cartridges.
The theoretical recoil energy is obtained by finding the recoil velocity (dividing the recoil momentum of the cartridge by the mass of the weapon) and then the banal MoruzhVerzh² / 2. And we get from several J to several tens of J. For example, in the notorious TT, the amount of gunpowder is 0.00052 kg (0.52 g), from which the recoil momentum of the cartridge is 3.3 kg * m / s, and the recoil energy of the gun is 5.98 J. In theory. Everything is different in life.
The weapon is held by the shooter, which means additional mass is added to the weapon. The movement of the weapon from the recoil is damped by the body of the shooter. Recoil can be "smeared" by the movement of the weapon's mechanics. DT or DTK can be used, in which the weapon is inhibited by the reactive action of gases. The maximum recoil force depends on the bullet's breakaway pressure, etc.
For comparison, let's calculate the characteristics of a couple of cartridges (according to one of the options):
9x19Steam: 8g, 360m/s, 0.4g of gunpowder: 518J, 3.39kg*m/s.
5.7x28: 2g, 716m/s, 0.5g of gunpowder: 513J, 2.07kg*m/s.
The muzzle energy of the bullet is almost the same, but the momentum is different.
By the way, as an independent work, I propose to think about why cartridges 5.56x45 and 5.45x39 are called not low-energy, but low-pulse. Why do the smart uncles involved in the development of weapons use such terminology?
We are primarily interested in the following conclusions:
The muzzle energy of a bullet is not a criterion for the recoil of a weapon.
For the same muzzle energy of a bullet, a cartridge with a heavier and slower bullet will always give more recoil.
It is convenient to use the recoil momentum of a cartridge only for assessing the recoil of a weapon and comparing cartridges, and not for calculating it, recoil, the exact value.
Bodies act on each other with forces equal in magnitude and opposite in direction.
(Newton's third law).
None internal forces unable to change the total momentum of the system.
(One of the formulations of the law of conservation of momentum).
First, let's define terms:
- Recoil is the movement of the weapon (barrel) back during the shot. (Fundamentals of shooting from small arms).
- Rollback of small arms. Recoil (NOT allowed -- small arms recoil) -- The movement of small arms under the action of the forces that arise when fired. (GOST 28653-90 Small arms. Terms and definitions)
- Recoil of small arms. Recoil. -- The forceful impact of small arms on the shooter, machine or installation as a result of a shot. (GOST 28653-90 Small arms. Terms and definitions).
As you can see, GOST separates the actual movement of the weapon and the force effect on the shooter, machine or installation. For the sake of simplicity, I will use the term recoil in its established first meaning as given in "Fundamentals of Shooting...".
Recoil options.
Return is characterized by several parameters:
- Pulse.
- Energy.
- Force.
- Power.
1. Recoil momentum.
By virtue of Newton's third law, two bodies interacting with each other acquire impulses equal in magnitude and opposite in direction. Numerically, the momentum of the force is equal to p=Ft, where p is the momentum, F is the force, and t is the interaction time. Also, the momentum of the body is equal to p=mv, where m is the mass of the body, v is the speed. With the momentum of the shot, everything is a little more complicated, because. not only a bullet, but also powder gases fly out of the barrel, so the recoil momentum is calculated according to the empirical formula
where m is the mass of the bullet, v0 is the initial velocity of the bullet, w is the mass of the powder charge, g is the acceleration of free fall, it is necessary to convert from the SI system to the technical system of units (from H * s to kgf * s).
According to the law of conservation of momentum (ZSI), the total momentum of a closed system (not interacting with external bodies) is a constant. Those. no automation is able to change the momentum of the weapon that it received as a result of the shot. The only way to influence the recoil momentum is to act on the propellant gases using, for example, DTK.
2. Recoil energy.
It's no secret that firing the same cartridge from a heavier weapon is more comfortable. The reason for this is the recoil energy is numerically equal to , where p is recoil momentum, and M- weapon weight, g - acceleration of gravity. In the technical system of units, energy is measured in kilogram meters (kgm). Because the weight of the weapon is given by us and is a constant value, within the tolerance during production, then according to the same ZSI, no automation is able to change the recoil energy of the weapon.
3. Recoil force.
Let's go back to the momentum formula p=Ft, p=const, but we have a value that we can influence - this is the interaction time t. Then, according to the same FSI, by increasing the interaction time by 10 times, we will reduce the recoil force by the same 10 times. . This effect has long been used in artillery, when the connection between the gun barrel and the gun carriage is through a recoil brake. The time of the shot is calculated in thousandths of a second during this time, the barrel with the bolt and receives a recoil momentum, but the effect, through the recoil brake, of the barrel on the gun carriage is a couple of orders of magnitude longer, respectively, and the force of impact on the gun carriage is as much less.
4. Recoil power.
Relationship between recoil and automation
Recoil is associated only with the automation that is actuated directly by recoil. This is a free and semi-free shutter, barrel recoil with a short or long stroke, etc. Systems that do not have automation at all or have automation not associated with recoil stand apart:
- A typical example of the first case is a three-ruler. It has no automation at all, however, there is quite a return to itself, surprisingly for some people who believe that the return is only when the automation is working.
- Systems with automatic vapor control and hard locking of the barrel. The most common case in individual infantry small arms - automatic. Automation there is driven by a gas engine, regardless of recoil.
Influence of recoil and automation on the accuracy of automatic fire.
First, let's talk about the correctness of the comparison. returns various types of weapons.
It is correct to compare two samples in terms of the recoil momentum only with approximately equal masses and automation schemes. For example, AKM, AK74, M16, G36 have a close mass and a gas outlet with hard locking, and their comparison in terms of recoil momentum will be correct. At the same time, it is correct to compare an assault rifle and a light machine gun under the same cartridge in terms of recoil energy, because with an equal or greater (for a machine gun) momentum, the recoil energy of the machine gun will be less than that of the machine gun due to the greater mass of the machine gun. Also, do not forget about the presence of various muzzle devices that can both reduce recoil (muzzle brake), prevent the barrel from moving away from the firing line (compensator), and increase recoil (recoil amplifier). And finally, the most correct comparison in terms of recoil power, the only way to fairly objectively compare a weapon with a gas outlet with hard locking and a weapon with barrel recoil during a long stroke or a gas outlet with braking of the recoil of the firing unit.
Features of dispersion during automatic fire
Classic picture from the manual...
A feature of dispersion when firing with automatic fire, especially from unstable and unstable positions, is that the main reason for dispersion is recoil and, to some extent, the influence of automation.
Let's consider the process in more detail:
- The weapon is aimed at the target, the trigger is released and the first shot of the burst follows.
- The bullet flies out of the barrel and the resulting recoil momentum begins to deflect the barrel of the machine to the right and up, while the bolt frame is moving and accelerating.
- The gases accelerating the bolt frame, according to Newton's third law, act not only on the piston, but also on the front wall of the gas chamber. They not only push the frame back, but also with the same force the body of the machine gun forward, trying to turn the barrel down.
- The bolt carrier with the bolt comes to its rearmost position and strikes the butt plate of the receiver in an attempt to tilt the barrel up.
- The bolt frame sends the cartridge and strikes in the forward position, additionally deflecting the barrel.
- Finally, a second shot follows and the whole story repeats itself.
The illustration shows graphs of the dependence of the area of the core of dispersion on the recoil momentum.
In 1964 A.S. Inappropriate, work was carried out to determine the dependence of the dispersion of automatic fire on the recoil momentum. Experiments have shown that with a decrease in the recoil momentum, the scattering area also decreases, i.e. when firing with a 7.62x39 cartridge, the main disturbing factor is precisely the recoil, but with a decrease in the recoil momentum, the contribution of automation increases (more precisely, the contribution of recoil decreases significantly). This is confirmed by the fact that automatic rifles with balanced automatics for a low-pulse cartridge have accuracy 2-3 times better than that of the AK74, and the automatic rifle with balanced automatics for the 7.62-mm cartridge tested in the 70s did not show any special differences from the AKM . The recoil momentum of the 7.62 mm cartridge interrupted all the efforts of balanced automation.
A small digression about balanced automation. It is widely believed that balanced automation reduces/compensates for or otherwise affects recoil. This is wrong. This automation is not driven by recoil, but by a gas engine, and for this reason alone cannot influence it in any way. It’s just that when firing, the powder gases do not press on the front wall of the gas chamber (there is no wall), but on the piston of the movable anti-mass, which is why the operation of automation has a minimal effect on the body of the weapon, and the impacts of the frame and anti-mass occur simultaneously in opposite directions and mutually neutralize. Recoil acts when fired at the bolt, and through it on the body of the weapon and the time of its impact is determined by the time of the shot, the weapon receives a recoil momentum long before the automation starts to work.
The rate of fire and why a fire monitor was needed.
As already mentioned above, the main reason for dispersion during automatic fire is the recoil and operation of automation. But the rate of fire affects the magnitude of this dispersion. At a rate of 600 rpm, 0.1 s passes between two shots, on the one hand it is very small (the rate is high), on the other hand it is a lot (the rate is small). Let's consider both cases.
- The pace is great. 1 tenth of a second is too small for the shooter to react and return the barrel to a position close to the original. This is clearly seen in the first illustration, the shooter manages to bring the machine gun closer to its original position only by the 4th shot, and the dispersion of bullets is large. Reducing the rate by 3-4 times is not an option, this means a decrease in the speed of moving parts and is fraught with a strong decrease in reliability. In addition, when shooting at a target moving across the line of fire, it can simply slip between the bullets of the burst due to the low rate of fire.
- The pace is small. 1 tenth of a second is too large and the weapon has time to deviate significantly from its original position before the next shot. If you increase the rate of fire, this will allow you to fire a short burst before the weapon has time to significantly deviate from the aiming point. Increasing the rate of fire requires complicating the weapon, at least introducing a cutoff.
- For balanced automation 4000-6000 rpm.
- For the carriage scheme ~ 2000 rpm for a two-bullet queue and 3000 rpm for a three-bullet one.
- For classical shock automatics, even an ultra-high rate of fire of 6000 rpm or more will not lead to the required improvement in accuracy due to high speeds of moving parts and strong impacts in extreme positions, which will lead to increased dispersion and breakdowns.
Looking at the required pace, it becomes clear why the fire monitor scheme was successful. She simply has the lowest required rate of fire, which immediately makes it easier to ensure the survivability of parts. Why is a two-three lower rate enough for a fire monitor, unlike other automation schemes? And here it is worth returning to the beginning of the conversation about recoil, and specifically to such a parameter as recoil power. The peculiarity of the carriage scheme is that the shooter perceives the recoil not directly, as in the usual scheme or in balanced automation, but through the shock absorber spring, which slows down the rolling unit. In weapons with conventional or balanced automatics, the recoil impulse transmission time is determined by the time of the shot, on the order of several thousandths of a second, while in a fire monitor, the time is determined by the recoil braking time t = 1/30 seconds, which is 10-15 times longer and, accordingly, the recoil strength and power 10-15 times less. Because of this, the deflection speed of the weapon is much lower and therefore the rate of 1800-2000 rpm is enough to fire the second shot while the deflection is small.
In the whole history of the Abakan competition, it was balanced automatics that turned out to be the most lagging behind. Even for classic percussion automation, it was possible to get around the problems with an ultra-high rate of fire. The creation of the AO-63 double-barreled machine gun made it possible to have a two-bullet burst rate of 6000 rpm and at the same time maintain the normal speed of the moving parts of the automation. Moreover, the AO-63 showed accuracy records from all firing positions.
“I like my 9.17mm because it has sharp recoil.”
“I hate my 9.17mm because it kicks like an angry donkey.”
“I don't want 10x22mm Smith & Wesson (.40 S&W) because the recoil force is too great for me.”
“My caliber .40 S&W has the softest recoil when fired, love it!”
“Calibre 9 mm - a good choice, it has controlled recoil.”
“I just bought a 9mm and it has terrible recoil…”.
The funny thing about all these statements is that they are all true! When assessing the recoil force of a firearm: 50 percent science, 50 percent opinion, and 112 percent magic. This is due to the fact that some recoil parameters can be expressed in numbers, which will have a completely unambiguous meaning for those who love physics. But other aspects of recoil are very subjective. And some factors depend on your physical form, the structure and strength of your hands.
Most of us have a complicated relationship with giving.
What creates returns?
We treat the concept of "kicking" weapons subjectively and make many assumptions. People assume that 9x17mm (.380 ACP) has no recoil, 9x19mm has little recoil, and other calibers recoil like hitting a brick in your mouth with a sledgehammer.
In reality, caliber does have an effect on recoil strength, but there are many other factors as well. The factors that determine how much recoil you will feel are the mass of the bullet, the mass of the powder charge in the cartridge, the speed of the bullet and gases, and the mass of the weapon. The forward movement of burning powder and gases at a certain speed creates an impulse directed forward. It must be precisely balanced by the momentum of the weapon moving backwards in the direction of the shooter. Because of Newton's third law, physics and stuff. The momentum per unit of time is the moment of force you feel, which we affectionately call recoil.
Which pistol has the least recoil?
Small calculations with these variables (bullet and powder weight, weapon speed and weight) will result in the number lb-ft (kg-cm) recoil forces. You might think that pound-feet is the amount of force at a certain distance. That is, one pound-feet measures the amount of force required to move a one-pound object over a distance of one foot, ignoring, for example, friction. But don't go too far in trying to compare the felt recoil of different weapons and ammo based on recoil force numbers alone. Because that's only part of the picture.
Several real values of recoil force ...
I said earlier that several mutually exclusive statements are true. I will briefly explain why. You can shoot any caliber cartridge, from a light, small pistol to a large, heavy one. A shot with a 9x17mm cartridge will be almost imperceptible, while the recoil from firing the same cartridge from a pocket pistol weighing several ounces can be felt quite strong. Let's look at a few examples. In them I use my data on the powder charge, since I equip them myself and know the weight of the powder in various cartridges. Usually for factory cartridges data on the charge of gunpowder are not indicated.
9x17mm: Ruger LCP and Beretta Cheetah
The Ruger LCP small pocket pistol weighs only 9.7 ounces, or about 0.6 lb without clip. For example, let's take the speed of a 90 grain 9x17mm bullet as 980 fps. This is the "average" value for factory-made .380 cartridges. The resulting recoil force is 5.59 ft-lbs.
The Beretta Cheetah pistol is much larger, with the Model 84 weighing 23 ounces without clip. Shooting a cartridge with the same bullet will give us a recoil force of 2.36 foot-pounds.
9x19mm: Smith & Wesson Shield and Sig Sauer P226
Shooting a 115-grain bullet with a 5.8-grain powder charge at 1233 fps from a 19-ounce Smith & Wesson Shield pistol in 9x19mm gives a recoil force of 7.26 ft-lbs. Firing the same cartridge from a full-size Sig Sauer P226 weighing 34.4 ounces produces only 4.01 lb-ft of recoil force. Much less than when firing a 9x17mm cartridge from a smaller and lighter pistol.
Moving on to the caliber that intimidates many beginners: firing a 230-grain 11.43x23mm (.45 ACP) bullet from a Smith & Wesson SW1911 eSeries pistol produces only 6.51 ft-lbs of force. You can do math all day, but that's only part of the equation. I mentioned these numbers only to show that a larger caliber may not have very strong recoil. It all depends on the weapon you use and your shooting technique. The force of the recoil can be compared to smaller caliber shots from lighter weapons.
Why do big pistols have less recoil?
Larger pistols are easier to shoot because your hand can properly wrap around the handle, and for several other reasons. First, pistols bigger size heavier, and the recoil force is inversely proportional to the weight of the weapon. More weight gives less recoil if all other parameters are the same.
And here's another reason why there is less recoil when shooting from large pistols, and the key word here is "felt." Big size grips usually means more contact area with your palm. The larger the contact area, the easier the felt recoil. For example, imagine shooting a 9x19mm pistol with just your thumb, middle and index fingers. Nothing else. In this case, you will definitely feel the shot. The gun will bounce and possibly even slip out of your hand. And your fingers will not be happy from such a shot either. Now imagine shooting from the same pistol, but with a beautifully shaped handle that perfectly follows the contours of each of your fingers and the entire palm. The shot will be much more comfortable, I guarantee. The extra contact area helps you control the weapon and provides more recoil application area.
Although, not everything is so simple!
To save time, space, and at the risk of putting you to sleep, we've only considered recoil force expressed in foot-pounds in this article. While this is not a complete picture, it does serve to show you the interesting differences in shots fired by different cartridges from different weapons. Digging deeper, we have to take into account things like recoil momentum, which is calculated based on the speed at which recoil interacts with your palm. This is one of the reasons shooters describe some caliber/pistol combinations as "harsh" and some as "soft". But we will save that for the next article.
In conclusion, I would like to ask you not to draw conclusions about recoil based on the caliber alone, without taking into account the weapon from which the shot will be fired. The weight and comfort of a weapon has a big impact on how much recoil you feel.
Based on an article by Tom McHale, author of the Insanely Practical Guides series of books that explain things from a practical point of view in an accessible and fun way.
Muzzle velocity and bullet energy, weapon recoil
Initial velocity is the speed of the bullet at the muzzle of the barrel. For the initial speed, the conditional speed is taken, which is slightly more than the muzzle and less than the maximum. It is determined empirically with subsequent calculations. The value of the initial velocity of the bullet is indicated in the firing tables and in the combat characteristics of the weapon.
The initial speed is one of the most important characteristics of the combat properties of weapons. With an increase in the initial speed, the range of the bullet, the range of a direct shot, the lethal and penetrating effect of the bullet increases, and the influence of external conditions on its flight also decreases.
The value of the muzzle velocity depends on the length of the barrel; bullet weight; weight, temperature and humidity of the powder charge, the shape and size of the powder grains and loading density.
The longer the barrel, the longer the powder gases act on the bullet and the greater the initial velocity. With a constant barrel length and a constant weight of the powder charge, the initial velocity is greater, the lower the weight of the bullet.
A change in the weight of the powder charge leads to a change in the amount of powder gases, and, consequently, to a change in the maximum pressure in the bore and the initial velocity of the bullet. The greater the weight of the powder charge, the greater the maximum pressure and muzzle velocity of the bullet.
The length of the barrel and the weight of the powder charge increase when designing weapons to the most rational dimensions.
With an increase in the temperature of the powder charge, the burning rate of the powder increases, and therefore the maximum pressure and initial speed increase. As the charge temperature decreases, the initial speed decreases. An increase (decrease) in initial velocity causes an increase (decrease) in the range of the bullet. In this regard, it is necessary to take into account range corrections for air and charge temperature (charge temperature is approximately equal to air temperature).
With an increase in the humidity of the powder charge, its burning rate and the initial speed of the bullet decrease.
The shape and size of the powder have a significant impact on the burning rate of the powder charge, and, consequently, on the muzzle velocity of the bullet. They are selected accordingly when designing weapons.
Loading density is the ratio of the weight of the charge to the volume of the sleeve with the inserted pool (charge combustion chambers). With a deep landing, the bullet significantly increases the density of loading, which can lead to a sharp jump in pressure when fired and, as a result, to a rupture of the barrel, therefore, such cartridges cannot be used for shooting. With a decrease (increase) in the loading density, the initial velocity of the bullet, the recoil of the weapon and the angle of departure increase (decrease).
To defeat a man kinetic energy bullets of normal caliber (6.5-9 mm) at the moment of meeting with the target must be at least 78.5 J. The lethality of a small arms bullet is maintained almost up to the maximum firing range.
The recoil of a firearm is the action when fired, mainly by the reduced force of the pressure of the powder gases applied to the barrel. The recoil causes a push to the shooter's shoulder or arm. The effects of recoil are reduced by a muzzle brake-compensator. In an automatic weapon, recoil is used to reload it.
The use of the recoil energy of a barrel moving relative to the weapon is one of the oldest and most successful principles for building small arms automation. In more than a century since the appearance of the first such systems in the world, the widest range of weapons with a moving barrel has been produced - from compact pistols to machine guns and automatic guns.
However, it should be noted that there are significant gaps in this spectrum. In particular, only a very small number of models of hand-held long-barreled weapons with such automatic equipment (smooth-bore guns and especially rifles) have achieved any noticeable success. Why this happened, we will briefly analyze below.
Recoil is a fundamental property of any throwing weapon, resulting from Newton's third law, which states that any mechanical action causes an equal but oppositely directed counteraction.
Hiram Maxim's patent for his first self-loading carbine using recoil energy
Hugo Borchard's patent for a pistol with a moving barrel, put into mass production in 1893
In our case, this means that throwing a bullet or other projectile with the force of expanding gases leads to the fact that the throwing weapon receives an impulse of movement equal to the total impulse of the projectile (bullet) and the powder gases that left the barrel, but directed in the opposite direction. It is this impulse that forms the recoil - the movement of the weapon in the direction opposite to the direction of the shot. In the case of weapons with a fixed barrel and a rigid locking of the barrel, all this impulse from the barrel is transmitted to the body of the weapon and through it to the hands or shoulder of the shooter or to the installation.
Sectional view of the legendary Mauser C.96 pistol
John Browning's patent for a long-stroke rifle that inspired the production Remington model 8 rifle
The first who managed to use in practice the previously wasted recoil energy of a weapon to carry out its automatic reloading was the American inventor Hiram Maxim, who at that time lived in Europe. In 1883, he filed a patent application describing a conversion of the Winchester repeating carbine with a Henry brace and underbarrel magazine.
Having added a spring-loaded recoil pad to the carbine, Maxim connected this recoil pad with a system of rods and levers to a shortened reload lever located in front of the trigger guard, so that with each shot, the movement of the entire carbine back relative to the recoil pad rested on the shoulder of the shooter caused automatic reloading of the weapon.
Soon, this highly experienced self-loading carbine was followed by the first fully automatic machine gun of its own design, in which the barrel with its shank and the bolt connected to them by a cranked pair of levers got the opportunity to move under the action of recoil inside the weapon box, stretching the return spring. This first machine gun was followed by others, and by the beginning of the 20th century, Maxim machine guns had become one of the most popular and successful weapons in their class for a long time.
The Colt model 1900 pistol was the first production moving barrel pistol designed by John Browning.
Colt model 1900 pistol, partially disassembled
Other inventors soon followed Maxim. In 1893, Hugo Borchard created the first more or less commercially successful self-loading pistol with a moving barrel. The very next year, the Mauser company received a patent for its version of a self-loading pistol using the recoil energy of a moving barrel, in 1896 John Browning joined this glorious cohort with his first “pistol” patents.
By the beginning of the twentieth century various options automation systems that use the recoil of a moving barrel have firmly taken their place among the most successful designs of self-loading and automatic weapons.
It should be noted that the main competitor of automation systems with a moving barrel - a system using the pressure of gases removed from the barrel with a fixed barrel, appeared almost simultaneously with the systems described here. However, for quite a long time, gas exhaust systems were noticeably less popular, and here's why.
Browning's "Auto-5" shotguns are probably the world's most widely used action-bore hunting guns.
John Browning poses in this photo with his M1917 machine gun, which, like the Maxim system, used a movable barrel and made the Maxim systems the most serious competition
An early long-travel Remington Model 8 self-loading rifle
Over a century old catalog page advertising Remington model 8 rifles
The earliest automatic weapons systems were created during the period of transition from black powder to smokeless; the intra-ballistic properties of the new smokeless powders were still very poorly understood, and the powders themselves could have very different characteristics in terms of the development of pressure in the barrel when fired.
At the same time, systems with a moving barrel depended only on the total recoil momentum during firing, and therefore were much less sensitive to variations in the powder charge and the projectile, provided that the total momentum received by the barrel at the time of the shot was within the limits determined by the designer, often pretty wide.
The main disadvantage of moving barrel systems was, as is usually the case, the source of its main advantages - that is, the moving barrel itself. In order to ensure the required reliability of the weapon in the conditions of the barrel expansion caused by heat, as well as accumulating soot or dust and dirt penetrating from the outside, the barrel, of necessity, had to have some gaps at the interface with the fixed elements of the weapon. This inevitably led to a loss in accuracy and accuracy of fire compared to systems with a fixed barrel.
In addition, the movable barrel needed support at least at two points - at the breech and in the muzzle of the barrel, or, in extreme cases, not far from its middle. Most systems with a movable barrel for this reason had a casing covering the barrel along its entire length (or at least to the front fulcrum), which inevitably increased the weight and cost of the weapon.
The M2NV heavy machine gun is another extremely successful example of a short-stroke system designed by Browning in the early 1920s and is still in service today.
Maxim machine gun in service with the British colonial troops, 1895
As a result of the foregoing, very few rifles with a moving barrel were produced in the world. The most successful (in terms of the number of issued) army models was probably the American Johnson Model 1941 rifle of the year (Johnson M1941), released in the amount of several tens of thousands of pieces.
The American hunting rifle Remington model 8 and its development model 81 became the most massive commercial model of a rifle with a moving barrel. Between 1906 and 1950, about 140 thousand units of this rifle designed by the legendary John Browning were produced.
For comparison, gas-operated self-loading rifles and carbines were produced on both sides of the conflict during the Second World War alone, with a total circulation of more than 10 million units. The production of machine guns with a movable barrel (Maxim, Browning systems, German MG-34, MG-42 and others) also amounted to millions of pieces over the same period.
True, there was one exception here - the self-loading shotgun of the same Browning system, known as the Auto-5, was produced in Belgium for almost 100 years, from 1902 to 1999, with a total production of over 2 million units. In addition, over 800,000 units of the licensed version of this system, the Remington model 11 shotguns, were produced in the USA. All other moving-barrel shotguns ever made in the world have not remotely been able to repeat this success.
In the period after the Second World War, in connection with the development of both knowledge about the internal ballistics and dynamics of weapons, and the creation of more advanced gunpowders, the development of new systems of machine guns with a moving barrel began to gradually fade away, giving way to simpler and more convenient systems with gas-operated automatics. . True, a number of structures created before the Second World War or during it still remain in service. First of all, these are the German MG-3 machine gun and the American Browning M2HB heavy machine gun.
The first model of the Maxim machine gun with a movable barrel
Johnson Model 1941 rifle, one of the few military rifle systems with a moving barrel that was mass-produced
But pistols with a moving barrel are still being produced all over the world in hard-to-calculate quantities, which can best be described as "millions of pieces a year." This is explained by the ease of use of this scheme when combining the functions of the automation engine and the locking unit in the weapon barrel.
The effect of a moving barrel on accuracy at typical "pistol" distances is very small, so moving barrel systems will remain the most suitable for use in powerful service and combat pistols for a considerable time to come.
Speaking about the technical aspects of systems with a movable barrel and its rigid locking at the time of the shot, it should be mentioned that all such systems, as a rule, are divided into two classes - “with a long barrel stroke” and “with a short barrel stroke”.
The German machine gun Mg.42, one of the most widespread and successful machine guns with a moving barrel, is still in service in many countries under the symbol Mg3
A Beretta APX pistol, incompletely disassembled to demonstrate the simplicity of modern movable barrel pistols.
Diagram illustrating general principles operation of systems with a long stroke of the barrel
In systems with a short stroke of the barrel, the length of its rollback under the action of recoil until the moment of disengagement from the bolt, as a rule, is significantly less than the length of the cartridge. Usually for small arms, this length ranges from 0.5 cm to 3 cm, after which the barrel and bolt are uncoupled, the barrel stops, and the bolt continues to move back under the action of accumulated inertia, removing and ejecting the spent cartridge case in recoil.
Then, in the roll forward, the bolt sends a new cartridge into the barrel and at the end of its path it again engages with the barrel for the next shot. In most long-barreled systems (for example, machine guns), the mass of the bolt, as a rule, is noticeably less than the mass of the barrel, so that most of the momentum accumulated during their joint initial recoil is "lost" uselessly when the barrel, after disengaging from the bolt, stops in the receiver.
In order to take advantage of this "wasted" momentum, many systems have introduced a so-called shutter accelerator. This mechanical device in the form of a lever or a pair of rollers interacts with the bolt and fixed structural elements of the weapon in such a way as to transfer part of the impulse from the barrel to the bolt by accelerating the bolt relative to the barrel with the barrel decelerating along the way.
In pistols, where the mass of the barrel and bolt are usually comparable, or even where the bolt is heavier than the barrel, such a scheme does not have practical application. Almost the only serial pistol that had a lever bolt accelerator in its design was created in the mid-1930s in Finland (Lahti m35) and had a relatively short and therefore light bolt.
This elegant Roth-Haenel self-loading rifle, produced shortly before the First World War, had an automatic design by Karel Krnk with a long barrel
Another little-known example of a moving barrel system is the Walther No.1 shotgun, which had a lever lock like the Makim or Luger systems, but lost outright to the Belgian Browning Auto-5 shotguns.
Long-stroke systems are distinguished by the fact that in them the barrel, coupled to the bolt, travels together the full recoil path inside the receiver, while the length of this path is necessarily greater than the full length of the cartridge.
At the end of the rollback, the bolt is intercepted in the rear position by a special sear, and the barrel, under the action of its return spring, begins to move forward. In this case, the bolt is first unlocked, then the barrel, moving forward, “leaves” the spent cartridge case remaining on the mirror of the fixed bolt. After the sleeve is completely out of the chamber, it is ejected from the weapon.
When the barrel comes to its extreme forward position, it automatically turns off the sear holding the shutter, and the shutter, under the action of its spring, rushes forward, sending a new cartridge into the barrel and, at the end of the roll, again engaging with the barrel. Due to the large mass and long path of movement of the movable system, structures with a long barrel stroke, as a rule, have a low rate of fire, as well as a slightly more complex design. Because they are much less common than systems with a short stroke of the barrel.
Today, the most popular class of weapons using automatic moving barrels are self-loading pistols.
As we have been able to see from this very brief overview, moving barrel systems have a number of undoubted advantages that determined their success, both in the early stages of the creation of automatic weapons and at the present time (though mainly only for self-loading pistols). The shortcomings of these systems have led to the fact that at present, in long-barreled weapons, gas-operated automatics have become the dominant scheme, which we will discuss in the next article.
In the next article in the series, you will learn about weapons that use the energy of powder gases vented from the barrel.
