When someone utters the cherished phrase that size does not matter, it is immediately perceived by most of those around him as a dirty joke or hint. But if we are not talking about a healthy lifestyle and not about relationships, but for example, about ballistics, then we can say with all confidence: the size is of great, if not decisive importance. And this is best seen on the example of a well-known Internet topic about why the Soviet Union abandoned the 7.62 mm automatic cartridge and switched to a much more modest 5.45 mm.
Since in 9.5 out of 10 cases, materials on “these Internets of yours” are written by people without the appropriate education, then the most correct decision in an attempt to get to the bottom of the truth will be to turn to some proven source. And who can better tell about the transition from 7.62 mm to 5.45 mm in the Kalashnikov assault rifle than the Kalashnikov concern itself? The latter today has several interconnected resources in the network, both trade and entertainment and information. In particular, we are talking about the division "Media". It was there that they managed to find the answer why the Soviet designers decided to abandon the 7.62.
So, not all 7.62 mm caliber cartridges were abandoned in the Soviet Union, but only automatic cartridges of this caliber developed in 1943. This decision was made due to the fact that the new automatic caliber 5.45 mm from 1974, despite its smaller size, had a number of serious advantages, which, in the context of the main infantry weapons, completely outweighed the available limitations. What exactly are we talking about?
Firstly, 5.45x39 mm cartridges were corny lighter than 7.62x39 mm - 10 grams versus 16 grams. The difference may seem small to the layman, but in reality it exceeds 30%. If we are talking about equipping at least 4 magazines with 30 rounds each, then 5.45 mm outperforms 7.62 mm by 720 grams! But even every fighter carries with him cartridges that are not equipped in stores, in paper bundles or in bulk. Thus, with a comparable mass, a soldier can take more rounds of 5.45 mm caliber. Do I need to say that in a war this is extremely important?
>>>>Ideas for life | NOVATE.RU<<<<
Secondly, 5.45x39mm produces noticeably less recoil. This, in turn, improves the accuracy of firing and its flatness by reducing the dispersion effect. In other words, fire using 5.45 is more effective both in single shots and in bursts. The range of a direct shot, the speed of the bullet increases. If in the automatic 7.62 it ranges from 293 to 760 m/s, then in 5.45 mm it starts from 922 m/s. Thus, the probability of hitting a target, including a moving one, increases.
Of course, 5.45x39 mm also had shortcomings that directly stemmed from its merits. The main disadvantage of the new automatic caliber in a number of special situations was that very high initial speed. Toward the end of the 1970s, Soviet gunsmiths needed to create a new submachine gun cartridge for silent shooting. It was required mainly for special units of the USSR, such as the Alfa group under the KGB of the USSR, formed in 1974. And then it turned out that it was extremely problematic to build a cartridge with a reduced bullet speed based on the 5.45 architecture. Therefore, Soviet designers did not reinvent the wheel where it was impossible and began to make special samples of silent weapons for special forces chambered for cartridges based on the 7.62 mm automatic caliber. Including for this reason, the "silent" "automatic" 7.62x39 mm remains in use to this day.
If you want to know even more interesting things, then you should read about Shpagin submachine gun: what happened to the legendary machine gun after the appearance of the AK-47.
Source: https://novate.ru/blogs/280422/62846/