Why in the Soviet army replaced the cartridge 7.62 5.45
Over the past two centuries in the production of military weapons there has been a tendency to reduce caliber. It is obvious to everyone that it is impossible to create the perfect weapon, so the designers are trying to make a rifle that will surpass all analogues. In 1974, a significant event occurred in the Soviet army: the AK-74 machine gun was used, which used a 5.45 mm caliber. Skepticism about this was quite unhealthy, and he was so ingrained that until now, some say that the 7.62 mm caliber was better. All technical characteristics in this article are taken from the work “That, from which they shoot in the CIS. Handbook of small arms "Alexander Bogolyubov.
Why did the change in caliber.
In addition to the trend mentioned above, there were 3 key reasons.
Former Chief Designer of FSUE “TsNIITOCHMASH” Shiryaev D.I. noted that during the first practical tests of ak-47 with a caliber of 7.62 mm, it turned out that when firing from an unstable position (for example, standing) in automatic mode, only 1-2 bullets fly at the target. This deficiency was planned to be eliminated at the factory revision, but this was not possible. For designers, it was obvious that using 7.62 mm caliber would be impossible to achieve.
Moreover, in the 60s, the Americans successfully switched to the 5.60 mm caliber with their M16A1, and at that time, this was a much more weighty argument, because once in the west they were able to create an accurate automatic rifle for shooting from unstable positions, and at the same time they used significantly smaller caliber, then the development in this area should bear fruit.
However, the main reason was the technical characteristics, which gave the rifle a new reduced caliber. To understand what the benefits of switching to 5.45 mm were, let's look at its advantages over the outdated 7.62 mm.
Advantages and disadvantages.
The caliber of 5.45 mm has a smaller cross-sectional area. Many advantages of the new caliber immediately follow from this: a more flat trajectory of the bullet's flight, a greater range of a shot, high accuracy, and also the preservation of a destructive force at a greater distance. It should also be borne in mind that since such bullets were 6 grams lighter (10.2 grams versus 16.2 from 7.62 mm), with 8 stores ammunition, each soldier will receive a weight saving of 1.4 kg, which is a very big advantage combat conditions. In addition, the structural features of the bullet make it "tumble" when hitting the target, thereby increasing the damage inflicted.
As disadvantages, it is worth emphasizing that the caliber of 7.62 mm due to the greater mass is less susceptible to the influence of weather conditions, that is, it shows itself a little better in combat operations in the mountains or forest areas.
Based on the foregoing, it becomes obvious that the transition to a caliber of 5.45 mm was a weighted and timely decision that allowed the Soviet machine guns to continue competition on an equal footing with Western counterparts.