Does it say somewhere in SR books that China uses Kalashnikov-copies? Because they might as well have gone the way of the Norinco QBZ-95
A large number of weapons are based on a patent, and they aren't copied very widely. The ones that are copied are generally the "legendary" (very widely known) weapons, like the RL AKs, M16s, M1911s, Beretta M92s, etc. There probably wouldn't be actual copies of weapons other than the most common ones, like the Ares Predator (which was already mentioned), the AKs (same) and a few others. There will probably be tons of weapons rather similar, differing mainly in looks and minor things (like +/- 100g weight, longer/shorter barrel, larger/smaller magazine) that cost about the same. The difference between a copy of a weapon and a weapon of the same type doesn't really translate to SR terms, but for an IRL example consider the Beretta M92
, the Taurus PT92
and the CZ75
You can bet that most firearms manufacturers mentioned in SR will make a wide range of guns (in addition to those actually mentioned in the books), so that each large manufacturer will have a weapon similar to the Ares Predator, a weapon similar to Beretta Model 101T, etc. Each will produce each type of gun that sells, and most weapons mentioned in SR3/CC are of the types that do sell.
Of course when many manufacturers are owned by the same larger corp, they might specialize. Since the owners of most of the firms in question haven't been mentioned anywhere, this is totally up to the GM.
The H&Ks are certainly not limited to Germany. The H&K MP5
is by far the most common SMG in existence and the standard one in just about every western police department and military force. Their pistols are used by the USSOCOM
and (hopefully) by the US Transportation Safety Administration. Since it's one of the few large European firearms manufacturers mentioned anywhere in the books, it's likely that H&Ks are extremely common everywhere in Europe, together with FN's guns.
I doubt there are many canon figures as to what the market shares of the guns manufacturers are, and I won't even try to hazard a guess (I haven't even got a clue what the numbers are IRL), but I can tell you for a fact that no one manufacturer will have a share as large as 50% in a broad classification like SMGs, nevermind pistols. It's hard enough to get as high as 30%, and already at that point the same guns seem to pop up everywhere. IRL, the only ones that might get close are Izmash in assault rifles or H&K in SMGs, the former especially if you consider all the license-built AKs (that are actually called AKs) to be Izmash weapons, too.