5.56×45 mm and 7.62×39 mm are the most popular automatic firearm cartridges. First the NATO assault rifle cartridge. The second is commonly associated with the AK-47 and its clones.
Due to its time-tested quality, many armies and police groups use these two cartridges. Good firing range, precision, and lethality have made ammunition popular. Both cartridges have unique attributes.
Both are good in specific ways. Internet debates regarding which cartridge is best to continue today. Finding the truth in a discussion is tough. Much depends on the shooter’s training, weapon expertise, and the weapon itself in actual battle.
Automatics/assault rifles are nearly typically built-in 5.56 (NATO) or 5.45 (Soviet/Russian systems), while sniper weapons and machine guns are still presented in 7.62×51 (NATO) or 7.62×54 ( Russia). First, we’ll discuss intermediate cartridges’ pros and cons.
When did the most common intermediate cartridges appear?
5.56×45 mm and 7.62×39 mm are standard intermediate cartridges. The Soviet intermediate 7.62×39 mm 1943 type is the grandfather.
The USSR’s development of the 7.62-mm intermediate cartridge opened new doors for constructing automatic weaponry. This cartridge was adopted in 1949 for the Kalashnikov assault rifle, AKA The AK-47.
Post-war, the 7.62×39 cartridge was frequently used with the AK. So widely that in the 1960s, NATO countries had to consider adding it as an automated cartridge.
However, it never came to that. In large part due to the appearance of the intermediate low-pulse cartridge 5.56×45 mm. This cartridge was developed in the USA in 1959 and went into production in 1961.
The cartridge was created based on the existing hunting ammunition .223 Remington. As with the Kalashnikov assault rifle, ammunition proliferation was facilitated by developing effective small arms.
For this cartridge, Eugene Stoner developed almost all of his models of small arms, including the famous M16 assault rifle.
The cartridge was widely supplied in NATO countries in the 1970s, and by the mid-1980s, it had become standard for all NATO countries.
The same conclusions preceded the development of intermediate cartridges in the USSR and the USA. Existing rifle cartridges were potent for modern models of automatic weapons.
Standard NATO cartridge 7.62×51 mm was overly heavy, affecting troop ammunition. This was unacceptable under new war conditions. Intermediate cartridges lowered weapon bulk, recoil, and burst fire range. The 7.62-mm cartridge weighed more than the 5.56-mm.
16 vs. 12 grams doesn’t seem like much. One hundred cartridges made a 400-gram difference. Consider the shooter’s eight regular magazines. The discrepancy is much more pronounced because portable ammo has gained a kilogram.
This is already very important for long march-throws. So, until 1974, the USSR also made a caliber 5, 45×39 mm intermediate low-pulse cartridge that is even lighter at 10 grams.
What are the pros and cons of cartridges 7.62×39, and 5.56×45
Both intermediate cartridges are utilized by world militaries today. It’s hard to say which is superior for the typical shooter owing to bias and personal preference.
To avoid this, it is common practice to rate ammunition in three main categories: power, recoil, and accuracy. With these categories, it is easier to make comparisons since all three parameters can be quickly evaluated both in theory and in practice.
The low-impulse intermediate cartridge 5.56×45 mm has advantages. Its bullet is nearly twice as light as 7.62×39 mm’s. Despite increasing flying speed, recoil impulse decreased.
This had a positive effect on the accuracy of shooting from automatic weapons. The automatic machine is trivially less shaky when firing in bursts.
It became more comfortable for the shooter to fire, scattering decreased, and therefore the probability of hitting the target increased. In addition to everything else, the trajectory of the board has improved due to the higher speed of the bullet.
A shooter using 5.56mm ammo is easier to aim, as fewer corrections for windage or elevation need to be made. This is especially important for long-range shooting.
The average speed of the bullet of the 7.62×39 mm cartridge is 720 m/s; for the bullet of the 5.56×45 mm cartridge, it is 1006 m/s. At 100 meters, neither cartridge reduces the bullet’s trajectory, but at 250 meters, the 7.62 mm bullet is decreased by 40 cm.
The bullet’s trajectory of the 5.56 mm cartridge is gentler and provides a longer-range effective direct shot. At a distance of up to 250 meters, it practically does not decrease.
Despite all this, the most prevalent automatic cartridge remains the Soviet 7.62×39 mm, which expanded thanks to the AK-47 and its licensed and unlicensed clones.
This ammunition also has some good things about it. First, and most obviously, is the weight of the bullet. This caliber is the best to use if you shoot at a target with body armor. A heavy bullet keeps its power much better at long ranges, making it a better killer and stopper.
Lower ricochet risk and more stable obstacle clearance are advantages of 7.62×39 mm ammunition. The bullet boldly overcomes thickets, leaves, and branches, while the 5.56-mm bullet can drastically change its trajectory due to a minor block.
Boards and bricks for 7.62mm ammo are often surmountable. When hitting bone, such a bullet is more dangerous. Low-pulse intermediate-caliber cartridges impact soft tissues more severely.
The 7.62×39 mm cartridge has a higher recoil. Strong recoil makes it difficult to make a clear second and third shot depending on the weapon and the shooter’s ability to fire accurately in bursts.
Low-pulse intermediate cartridges have a flatter trajectory, making them easier for mass armies with a conscription system to train. Not for nothing is the 5.45 mm cartridge Russia’s most popular. The military is considering returning to 7.62 mm or producing new ammo.
If we sum up the results by comparing the three main criteria, everything here is quite simple. The intermediate cartridge 7.62×39 mm wins in power but loses to the 5.56×45 mm in accuracy and recoil.
For the average shooter, the intermediate low-pulse cartridge 5.56×45 mm and its Russian counterpart 5.45×39 mm when firing at long distances is preferable.