OK, I'm a long time shooter of corrosive ammo, and I'm here to give you the straight dope on this stuff. Yeah, some of the Russian stuff is corrosively primed. Typically this is older stuff, but Russians being Russians, they are not above slipping corrosive primers in on us sometimes. If you get 7.62X39 from any surplus source assume it's corrosive.
Now, clean up. I've heard a lot of people swear that ammonia is a neutralizing agent for corrosive ammo. It's not. Ammonia does nothing-it's unnecessary. What does the work is the water. Glass cleaner is mostly water. Water, you say? Horse apples, you say? Nope, and I'll tell you why. What makes the primers corrosive are the salts the leave behind. These salts need to be removed (not neutralized, removed) to prevent corrosion. I've cleaned many, many guns with nothing more complex than hot water. I mean really hot, OK, like from the stove just below boiling hot. Simply pour down bore using a funnel. But the water! It'll make it rust! No, it won't. Boiling or near boiling water will heat the metal to the point where the water evaporates. You scrub the bore with a brush and heated water to remove the salts from corrosive priming, then clean and lubricate as normal. This gets more complex with the AR15 platform, I get that, but most modern cleaning solvents will not remove corrosive salts from this type of ammo. Yeah, Hoppes too- they made them remove that part of the formula, it's bad for the environment. Us old guys know it smells different now than it used to, and that's why. Hope this helps guys.