I've got a Colt 9mm SMG I bought as a complete de milled part's kit, came with all the parts including the mag section of the receiver and the 3-round burst trigger ... I've got 2 Colt mags & a C-Products which has been good, then I picked up 6 plastic Pro-Mags and I've put a few hundred problem free rounds through them, all shot in full-auto with my Colt M16 lower.
If you really want something you'll find a way ... ... if you don't you'll find an excuse.
I'm really not a "kid" anymore ... but I haven't grown up yet either
Brownells FTW! I have 10 of them and recommend them highly. They are indeed made by Metalform, but to Brownell's specs. The Xylan coating makes them literally wipe clean with a paper towel. Super slick and very durable. Well worth the $$.
I've metalform mags in volume in lots of different forms and finishes and guns. Very old ones, new ones, somewhat old ones etc. etc. I have never had a bad one. The very early blued colt ones need constant maintenance to avoid rust but that's it. On the other hand I was given a large batch of promag ones, I used them since they were free but all (100%) of them eventually failed. I bought a large batch of ASC ones as the price was 1/4 of a genuine metalform. The failure rate was high enough that was not a good deal. SO over lots of mags, guns and rounds, if it counts run metalform. If it doesn't use what you want. FWIW>
“So in war, the way is to avoid what is strong, and strike at what is weak.”