A little something to remember about MegCar mags...
It is true they they are fully capable of making excellent magazines, and do so on a regular basis, but there may...or may not be...a difference between the mags they produce for retail sale and those thjey make to say, Sig or Beretta factory specs. These tend to be made on contract and they will, of course, build the factory whatever it wants. I have seen the specs for Beretta's mags built by them, and they are very, very strict about such things as double heat treatment, etc. In addition, if they find a single bad one in a lot, they reject them all...or at least they used to. Considering the fact that they cost only a bit less than factory mags, I would not take the chance if buying them for serious use.
Having said that, I will also admit that I have several of their Sig 220 mags that have worked flawlessly for years, while I had two factory-provided mags that separated at the rear seams!