Below shows some good deals on the Sar USA B6 pistol. I don't know how long this specific model has been available. If I'm not mistaken, it is a polymer clone of the CZ 75 or the CZ 75B. Most CZ 75B magazines are 16 round ones made by Mec-Gar. I think Mec-Gar is OEM for the CZ 75B.
Will the Sar USA B6 below take the 16 round Mec-Gar magazines made for the CZ 75B?
Yes and No.
The Standard 16 round Cz75B Mec-Gar Magazines with the metal Floorplate will fit, but they will only seat, so long as the SAR B6 Slide is locked back upon insertion.
It's a touchy fit. The Standard 16 round Cz75B Mec-Gar Magazines with the Polymer Floorplate are mostly a No-Go, unless you want to try sanding down the top of the Polymer Floorplate.
The Mec-Gar Cz75B Magazines that do work best with the SAR B6/B6P are the 17 and 19 round AFC (Anti-Friction Coat) Magazines, and that is exactly what I recommend using.
The 19 rounders are now all I use in my SAR B6P.
SAR B6P and K2P with Mec-Gar Cz75B 19 and 17 round AFC Magazines
Also note, that while the SAR B6 is considered a Cz75 Clone, it's more of a Clone of the Tanfoglio Cz Clone Pistols.