If you look at the German and then the Soviet tanks during the Second World War, you will notice one important difference. Many, though not all, Wehrmacht tanks have a muzzle brake. In Soviet tanks, it is most often absent and is found only on self-propelled guns with a large caliber, as well as in some late heavy tanks like the IS-2. At the same time, not everyone knows that Soviet tankers literally opposed the installation of a muzzle brake. Why?
First, you need to figure out what function the muzzle brake performs on the gun, in principle. The main purpose of the muzzle brake is to absorb recoil energy. With such a device, the gun rolls back 50-60% less, which can significantly reduce the size of the recoil device. This is especially important for tanks and self-propelled guns, since the gun takes up less space under the armor, which means that the profile of the vehicle can be made lower and narrower. In addition, the muzzle brake removes most of the powder gases from the barrel, thereby seriously increasing the comfort of the crew by reducing the gas contamination of the inner space of the combat vehicle at the time of the shot.
Ultimately, the muzzle brake allows the use of more powerful and longer guns with the same dimensions of a tank or self-propelled guns. It increases the initial velocity of the projectile, which means that the power of the shot also increases. The combat effectiveness of the tank is increased. True, the muzzle brake also has a number of disadvantages. It was they who made it extremely undesirable for Soviet tankers.
First, the powder gas scattered from the muzzle brake severely limits the gunner's visibility, making it difficult for him to work on target observation. In some cases, the gas and dust raised by it can even contaminate the gunner's optics. Secondly, the escaping smoke decisively unmasks the tank during the firing, thus depriving it of its tactical superiority and the effect of surprise the next time it is fired. Thirdly, Soviet tanks were actively used for maneuverable attacks and counter-offensives, including as amphibious assault vehicles. However, the scattering hot gas could injure people on the armor, which would make it impossible to combine transportation and simultaneous shots.
As a result, Soviet tankers preferred less powerful weapons to maintain the tactical flexibility of medium and some heavy tanks. By the way, on almost all modern tanks the classic muzzle brake is also missing.
If you want to know even more interesting things, then you should read about SPG: the short and eventful life of the "tank hunters" of the Second World War.