The two 7rd ProMags I bought for my Thunder 380 have worked fine thus far. The ones I just got for my 380CC seem to work just as good as the Bersa mags, although I've only fired 100 rounds through each. But anything can happen at any time. My 8rd Bersa and ProMags fit the Thunder 380. The sales person said they wouldn't, but I've read on some forum that they would. Sooooo I tried them, 8rd mags in my 7rd Thunder 380. Not a hiccup or a burp, not once. Have not tried the 7rd mags in the 8rd CC though. Another experiment for another day when I can find ammo!
ProMags for my Beretta 92FS seem to work fine. As do their mags for my S&W 908. Some folks may have had problems in the past or they heard some guy have problems with them... But I personally haven't had one misfire, FTE, FTF with any of my ProMag products. Don't buy them because I bought them. Hell, I'm not tied to them in any way. Ask your range guy and see what they use. Surely for range guns they must use something other than factory magazines!
Keep your powder dry...
Wagonboss