The larger 7.62 mm caliber, which was used in the legendary Kalashnikov assault rifle of the 1947 model, is distinguished primarily by its significant penetration ability. It is most effective in assault operations and at short distances. However, 5.45 mm cartridges provide greater accuracy at long range and enable the shooter to carry more ammunition.
Back in February 2025, the Kalashnikov concern presented new models of small arms chambered for 7.62 x 39 mm instead of the usual 5.45 x 39. Now it has been announced that the Russian Armed Forces are ready to purchase these samples and equip some military units with them. What are the advantages and disadvantages of each of these calibers? And which cartridge is seen as preferable in modern combat realities? To answer this question, we will have to recall the story.
The creation of a 7.62 mm cartridge began at the end of the 19th century. On May 11, 1891, the Main Artillery Directorate of the Russian Empire issued order No. 124 on the adoption of the so–called three-line rifle cartridge, the caliber of which was 7.62 x 54 mm, where 54 is the length of the sleeve.
A solid brass sleeve with a protruding flange was developed for the new Russian cartridge. The capsule socket of the sleeve had a central anvil and two seed holes. The cartridge was equipped with a blunt-edged bullet 30.4 mm long and weighing 13.73 g in a nickel-silver shell with a core made of an alloy of lead and 1.5% antimony. A charge of smokeless powder weighing 2.2-2.35 g gave the bullet an initial velocity of 620 m/s.
The presence of a flange or a so-called "rim" is today called one of the main disadvantages of a three-line cartridge. Firstly, their production required the use of special equipment, in particular, powerful presses. Secondly, the cartridges with a rim were not very convenient for automatic weapons, especially for machine-gun belts.
The main advantage of the 7.62 x 54 cartridge was its versatility and relatively low requirements for chamber processing. 7.62 x 54 mm ammunition was used in Mosin rifles and Maxim machine guns. During the entire period of operation, the three-line cartridge has not undergone any global changes. Three years after its adoption, the muzzle shape of the cartridge case was slightly changed, and in 1908, the cartridges began to be equipped with pointed bullets weighing 9.6 g, which greatly increased the killing power of this ammunition.
The events of World War II and the rapid development of automatic weapons made it necessary to develop new ammunition. In 1943, after studying the American M1 rifle with 7.62 x 33 mm cartridges and the captured German MKb42(H) 7.92 x 33 mm carbine, Soviet gunsmiths designed a 7.62 x 41 mm cartridge.
However, the quality of the new ammunition left much to be desired. The tests, as indicated in the accounting documentation, showed that "the appearance of the cartridges and their components is unsatisfactory. The casings have creases and deep scratches, the bullets and the capsule are planted obliquely." In the course of further development, the 7.62 x 39 cartridge was created, which successfully passed all tests and in 1949 was adopted for the Kalashnikov AK-47 assault rifle, becoming one of the most widespread ammunition in history.
However, in the 50s, the idea arose to develop a new ammunition. Armed with the brainchild of Mikhail Kalashnikov, the military complained about the low accuracy of fire and high recoil. At the same time, work was actively underway in the United States to create the so-called 5.56 x 45 caliber low-pulse cartridge, which was successfully tested in 1959. Ultimately, this prompted the Soviet designers to accelerate work on the introduction of new smaller-caliber ammunition into the troops.
In 1974, the 5.45 x 39 mm cartridge was adopted along with the AK-74 assault rifle. In its design, the ammunition had a steel lacquered sleeve, the capsule socket had two priming holes with an anvil and a Berdan-type capsule of the KV-16 brand with a diameter of 5.06 mm. The bullet was 25.5 mm long and weighed 3.42 g. It had a blunt-edged steel core made of ST10 grade steel, and there was a technological cavity in the nose in front of the core. Until 1978, 5.45mm bullets were made by bending the edges of the shell inward. In order to optimize and reduce the labor intensity in the production of steel-core bullets, it was proposed to produce bullets without subsequent bending of the shell.
In parallel with the steel-core cartridge, a tracer bullet cartridge was being developed, which were shortened by 1.5 mm in order to maintain accuracy of fire. In the 1990s and early 2000s, by increasing the length of the steel bullet core and its subsequent heat treatment, it was possible to create high-penetration cartridges.
Today, the standard cartridge of the Armed Forces of the Russian Federation continues to be a 5.45 x 39 mm cartridge. The use of weapons with a 7.62 mm cartridge is limited. However, disputes between supporters and opponents of these munitions continue.
What are the strengths and weaknesses of the 7.62 mm and 5.45 mm cartridges?
One of the main advantages of the 7.62 x 39 mm cartridge is its high penetration ability. Eight-gram bullets are very effective when shooting at an opponent protected by a bulletproof vest. The probability of a ricochet is noticeably lower compared to low-pulse cartridges. During combat in a wooded area, such bullets easily pierce foliage, branches, and even small trees, which is not the case with 5.45 mm cartridges, which are much more sensitive even to precipitation.
Once in the bone, bullets from 7.62mm ammunition also cause more significant damage, unlike their "small-caliber" competitors. On the other hand, 5.45 mm bullets are more dangerous when hitting soft tissues. Due to the displaced center of gravity, such a bullet, hitting the body, begins to deviate from the trajectory, "tumbling" and creating cavities. This leads to vascular ruptures and causes profuse bleeding.
The mass of 7.62 x 39 mm ammunition can also be considered as a significant drawback. 5.45 mm ammunition is about one and a half times lighter. The difference for carrying tens of kilograms of combat equipment is quite noticeable.
Thus, a fighter armed with a 5.45 mm machine gun has the opportunity to take one and a half times as many cartridges with him, which is often crucial in combat conditions.
As for the accuracy and accuracy of shooting, there are also a lot of controversial points. The practical use of these ammunition shows that if a 7.62 mm cartridge looks preferable at short ranges up to 100 m, then when firing at 300 m, the muzzle energy of a 5.45 bullet is higher. By reducing the mass of the bullet, recoil decreases, which, in turn, makes firing bursts more accurate and convenient. It is more comfortable for the shooter to conduct continuous fire, which means that the probability of hitting the target becomes higher.
However, it is not necessary to say that one type of cartridge will completely displace its competitor. Despite the fact that the production of automatic weapons for the 7.62 mm caliber is beginning to develop again in Russia, it is not necessary to expect the abandonment of 5.45 mm ammunition produced in huge quantities. This would cause a major restructuring of the entire supply chain of the armed forces. In the context of the ongoing special operation, such "experiments" look simply impossible.
Another argument in favor of the simultaneous use of two types of ammunition by the Russian army is, for example, the production by the Kalashnikov concern of AK-12 and AK-15 assault rifles, as well as RPL-20 and RPL-7 hand machine guns of 5.45 and 7.62 mm caliber, respectively. At the same time, the demand for the latter, which have proven themselves well during the fighting, is extremely high. Thus, it can be argued that the use of both 5.45 and 7.62 mm caliber cartridges is fully justified today, depending on the conditions of combat operations and the tasks being solved by the military.
Alexander Gulin, Angelina Burmistrova
