Same for the p99. I can think of at least 3 different makers of that gun as well. Is it patent related or do these original makers sell the rights to make these clones or what
The two most prevalent "clones" of the P99 (the S&W SW99 & Magnum Research MR9) were more like joint ventures than actual clones, since Walther actually made the frames of those pistols. Many parts (icluding mags) are interchangeable between the P99, SW99, and MR9.
The Canik TP-9, which looks a lot like the P99, is actually quite different mechanically, with no parts that interchange with the P99.