Gun manufacturers and military analysts give each weapon a length in yards (or meters, if they’re so inclined). This distance is supposed to be the farthest that an averagely-trained soldier using that weapon is supposed to be able to hit a man-sized target consistently. But this number is rather controversial.
Why would that be? Mainly because the way that people find that number is different. For example, Jane’s Defence rates handguns and rifles by finding out how far an averagely trained soldier can hit the target once using the entire magazine. That means that a match-grade .357 revolver (with 6 rounds in the cylinder) would have the same number as a standard 9mm autoloader (with 15 rounds in the magazine).
The Russians are the worst at this. They measure how far the bullet will travel under absolutely favorable conditions and they then assign that number to their guns (they call this the “killing range”). What’s wrong with this? Well, the bullet would have lost most of it’s velocity by the time it reaches the end of it’s flight, so it certainly can’t be expected to kill anyone if it’s just kisses your T-shirt and drops to the ground. In fact, most bullets would have slowed down below killing speed before they reach the mid-way point.
Another factor is that most russian arms just aren’t that accurate. Sure, they’re very robust and easy to maintain, but it’s rather problematic to actually hit anything at even half the distance that Western arms can easily perform.