The question of what caliber is used in the legendary Kalashnikov assault rifle often causes controversy among small arms and history buffs. Many people mistakenly believe that there is only one standard, but the evolution of these weapons has led to the use of several types of ammunition. The main and most famous option, which is associated with the classic AK-47, is an intermediate cartridge of 7.62 mm caliber.
It was this ammunition that became a symbol of the reliability and power of the Soviet and then Russian army design school. It provides high stopping power at medium and short distances, making it effective in real combat. Understanding the characteristics of this cartridge is necessary not only for historians, but also for modern owners of civilian weapons who use its hunting modifications.
In this article, we will examine in detail the physical properties of the ammunition, its difference from more modern analogues, and the reasons why it has remained relevant for more than seventy years. You'll find out why 7.62×39 mm has become one of the most common cartridges in the world and how its parameters affect the design of the machine itself.
Historical context and development of the ammunition
The development of a new intermediate cartridge began in the Soviet Union during the Great Patriotic War, when it became obvious that the 7.62x54 mm R rifle cartridge was redundant for automatic weapons at distances up to 400 meters. A solution was required that would combine the compactness of a pistol cartridge and the penetrating power of a rifle cartridge. The result of long tests was the appearance of a cartridge 7.62×39 mm model 1943.
Initially, this ammunition was intended for the Simonov self-loading carbine (SKS) and the Fedorov-Simonov automatic rifle, but it was in conjunction with the Kalashnikov assault rifle that it revealed its full potential. The design of the cartridge case and the powder charge has been optimized for trouble-free operation of the automation in the harshest conditions. This made it possible to fire even after the weapon was immersed in water or sand.
⚠️ Attention: When studying the history of the cartridge, it is important not to confuse it with the German 7.92x33mm Kurz cartridge, which was used in the StG 44. Although the concept of the intermediate cartridge was similar, Soviet engineers created a completely independent design with different ballistic characteristics.
Mass production of the cartridge made it possible to saturate the army with effective ammunition, which was lighter than rifle ammunition, but more powerful than pistol ammunition. This became a key factor in increasing infantry mobility. A soldier could carry significantly more ammunition without a critical increase in load, which directly affected combat tactics.
Why 7.62?
The designers chose the 7.62 mm caliber, since it had already been mastered by industry (Mosin rifle bullet). This made it possible to quickly establish the production of new bullets, using existing equipment for their production, changing only the length of the cartridge case and the charge of gunpowder.
Physical characteristics of the 7.62×39 mm cartridge
The main caliber of the classic AK-47 is 7.62 mm, but the cartridge markings always indicate two values: bullet diameter and cartridge case length. The complete nomenclature looks like 7.62×39 mm. The first number denotes the diameter of the barrel and bullet, and the second is the length of the cartridge case, which is critical to the chamber of the weapon. The use of a cartridge with a different case length in a weapon is strictly prohibited.
The bullet of this cartridge has a steel or bimetallic jacket and a lead jacket. Inside there is a steel core that provides high penetration power. Bullet weight varies depending on the type of ammunition, but a standard military bullet weighs about 7.9 grams. The initial speed of departure from a 415 mm long barrel is approximately 710-720 meters per second.
The energy of the shot is also an important characteristic. The muzzle energy of a standard cartridge is about 2000 Joules. This is enough to penetrate a standard steel helmet at a distance of up to 600 meters and penetrate brickwork or timber of considerable thickness. Such indicators make this caliber a universal tool for solving a wide range of combat missions.
The main feature of the 7.62x39 mm cartridge is the optimal balance between penetration and recoil, which allows for effective burst fire with acceptable accuracy.
The cartridge case is most often made of steel with a varnish coating, which reduces the cost of production and increases corrosion resistance compared to brass. The primer is ignition, combat, and ensures reliable ignition of the powder charge even at low temperatures. It is the reliability of ignition that is one of the key requirements for military ammunition.
Comparison with low-pulse 5.45x39 mm cartridge
At the end of the 1970s, the AK-74 assault rifle, using a reduced-caliber cartridge, was adopted by the Soviet army. 5.45×39 mm. This change was dictated by the global trend towards caliber reduction, which began in the USA with the adoption of the 5.56x45 mm cartridge. The transition to a smaller caliber made it possible to increase the soldier’s wearable ammunition and improve the accuracy of fire at long distances.
The main difference is the bullet's trajectory. The low-impulse 5.45 mm cartridge has a flatter trajectory, which simplifies aiming and reduces the influence of side winds. However, a smaller caliber bullet has less stopping power and is less capable of penetrating obstacles such as tree branches, light cover, or items of equipment compared to the heavy 7.62mm.
- 🎯 Caliber: 7.62 mm versus 5.45 mm - the difference in bullet diameter is more than 2 mm, which significantly affects the area of the wound channel.
- ⚖️ Weight: The 5.45mm cartridge is lighter, allowing the soldier to carry more rounds with the same load.
- 📉 Recoil: The recoil impulse of the 5.45 mm is significantly lower, which increases shooting comfort and the speed of the weapon returning to the aiming line.
- 🛡️ Breakthrough: 7.62 mm better retains energy when passing through obstacles, which is critical in urban areas or wooded areas.
Despite the Army's transition to 5.45mm, the 7.62x39mm cartridge was not completely phased out. It remains in service with special units, is used in short-barreled assault rifles (AKSU) and is widely used in the civilian sector. Hunters and sportsmen value it for its availability and effectiveness against large game.
Ballistic properties and firing range
The ballistics of the 7.62×39 mm cartridge has its own characteristics that must be taken into account when shooting. Due to the relatively heavy bullet with low sectorial density (the bullet quickly loses speed over long distances), the flight path is steep. The target firing range of a machine gun is usually limited to 1000 meters, but effective shooting at a tall figure is carried out at distances of up to 300-400 meters.
At a distance of 100 meters, a bullet penetrates a steel plate 2 mm thick, and at a distance of 300 meters - 1 mm. This demonstrates the high residual energy of the ammunition. However, after 500 meters the bullet becomes unstable and can ricochet off hard surfaces at sharp angles, which creates a danger for the shooter and others.
An important parameter is the accuracy of the battle. For the AK-47, standards allow bullets to spread within 15 cm at 100 meters when fired from a rest. In real conditions, when shooting handheld, this figure is much worse. However, the density of fire and the probability of hitting a target when firing in bursts compensate for the low accuracy of single shots.
| Distance (m) | Bullet speed (m/s) | Energy (J) | Penetration (steel, mm) |
|---|---|---|---|
| 0 (muzzle) | 715 | 2040 | 12 |
| 100 | 620 | 1550 | 8 |
| 300 | 440 | 780 | 4 |
| 500 | 290 | 340 | 2 |
It is worth noting that the data in the table is for a standard steel core bullet. The use of special bullets, such as tracer or armor-piercing bullets, can significantly change these indicators. Tracer bullets have less mass and lose speed faster, but allow you to adjust the fire visually.
Types of bullets and their purpose
The ammunition industry offers a wide variety of 7.62x39mm bullets, each with a different color designation on top and a specific combat application. Understanding the markings allows you to quickly identify ammunition and choose the best one for a particular situation.
The main live cartridge (BP) has a bullet without a color coating or with black varnish. Inside there is a steel core that ensures penetration of helmets and light shelters. Armor-piercing incendiary bullets (AP) have a black body with a red belt and are designed to ignite flammable liquids and penetrate armor.
- 🔴 Tracers (T-46): The red color of the top allows you to see the trajectory of the bullet to adjust the fire in the dark.
- 🟡 Incendiary (Z): Green color, intended for igniting dry materials and flammable mixtures.
- 🔵 Armor-piercing (AP): Black in color, they have a reinforced core made of hardened steel or tungsten carbide to penetrate heavy obstacles.
- ⚪ Blanks: Do not have a bullet, are used to simulate shooting and fireworks, require replacement of the barrel or installation of a muzzle device.
⚠️ Attention: The use of live ammunition in civilian weapons (for example, in hunting carbines such as SKS or Saiga) is permitted only with the appropriate license and in specially designated areas. Shooting in populated areas is prohibited by law.
There are also cartridges with reduced bullet velocity (UVS), which are used in combination with silent shooting devices. The bullet of such a cartridge has a special design and weight that allows it to remain in the sound shadow (not create a shock wave), which makes the shot almost silent. However, the range and penetration of such cartridges are significantly reduced.
Use in civilian weapons and hunting
In the civilian market of Russia and the CIS countries, the 7.62×39 mm cartridge is one of the most popular. Many hunting rifles have been created on its basis, such as Saiga-MK, Vepr-KM and their various modifications. These samples are structurally similar to the Kalashnikov assault rifle, but have limitations provided for by law (for example, the inability to fire in bursts or a shortened barrel).
Hunters value this caliber for its versatility. It is suitable for hunting medium-sized ungulates such as wild boar, roe deer or deer at distances of up to 200 meters. A soft expansion bullet, approved for hunting, causes serious damage and ensures the rapid termination of the animal’s life, which is consistent with the principles of humane hunting.
For loading cartridges at home (for reloading license holders), brass cartridge cases, bullets and primers are produced. The recharging process requires care and safety precautions. It is necessary to strictly observe the weight of the powder charge, since the use intermediate cartridge implies high pressures in the barrel.
☑️ Checking the cartridge before shooting
The cost of the civilian 7.62x39 mm cartridge is usually lower than that of the 5.6x39 or .308 Winchester hunting calibers. This makes it attractive for zeroing weapons, training and sport shooting. The availability of ammunition in stores allows gun owners to maintain their shooting skills without significant financial costs.
FAQ: Frequently asked questions
Can an AK-47 be fired with 5.45mm ammunition?
Absolutely not. The cartridges have different bullet diameters (7.62 versus 5.45) and different case lengths (39 versus 39 mm, but the bottom diameter and groove are different). Attempting to insert a cartridge of a smaller caliber will result in jamming or destruction of the weapon when fired, which is fatal for the shooter.
What is the maximum range of a 7.62 mm bullet?
The maximum flight range of a bullet when fired at an angle of 45 degrees can reach 2000-2500 meters. However, the effective aimed firing range is much shorter and is about 400 meters for single shots and up to 800 meters for machine gun fire at group targets.
What is the difference between the 7.62x39 and 7.62x54R cartridge?
The main difference is the length of the sleeve and power. 7.62x54R is a powerful rifle cartridge used in machine guns (PKM) and sniper rifles (SVD). It has a raised rand (R) case and significantly more energy than the intermediate 7.62x39 used in assault rifles.
Why does a 7.62mm bullet ricochet?
The bullet has a rounded head and is made of hard material (steel/tompak). When it hits hard surfaces (concrete, stone, ice) at an acute angle, it does not collapse, but changes direction of flight, retaining most of its energy, which makes the ricochet extremely dangerous.
Is this cartridge used in the modern Russian army?
In line infantry, the main caliber remains 5.45x39 mm. However, the 7.62x39 mm cartridge continues to be actively used in special units, as well as as the main ammunition for Kalashnikov light machine guns (RPK) in some modifications and for short-barreled assault rifles, where compactness and penetrating power are important.