The murder rate would triple overnight, at LEAST.
And shee-yit you aren't going to just ban guns in those soviet block countries. I know someone, I won't say who or where or where from. But lets just say I've seen a pic of that person's stash and christ, would make an american gun nut foam at the mouth..heavy machineguns/autocannons, pretty sure I remember seeing at least a few bloody rocket launchers, plastique, lets just say if all goes postal, I know where I'm headed, or rather who I want to hook up with.
And I shudder to think how much the bugger's got hidden in caches. Don't underestimate the effects of WWII on the eastern european psyche as a whole. Massacres in poland etc. And there are so MANY untracked weapons in the hands of people like this individual that there is no way in hell they want their guns taken from them.
And to make a point-an AWFUL lot of the illegal handguns are russian 9mm Makarov semi-auto pistols, or one of the equivalent polish, hungarian etc. copies (pretty much every country and their family dog bar the USA and UK have either directly used or copied the russian 9mm Makarov, or in the case of the chinese, butchered of course) Bloody lot of the things around and your average underworld figure wouldn't have to cough up that much for one.