Not to add a wrench to your thought process, but have you considered PMags? All the rage right now, and seem to be very robust. There are great deals a lot of places (Palmetto State Armory (a sponsor here) for one, $10 each IIRC - the 'non M revision' model, but those are still fine - just the cap won't fit the bottom - if you look into a bit, this will make sense). There are many links to some impressive independent torture tests on them.
Madness is like gravity; all it needs is a little push.