Old thread alert
I bought 4 @ $16.50. All are functioning (now), easy fixes.
Here's the feed issue fix:
http://www.youtube.com/watch?v=Qd_REKhNNeQ (if you're interested, here's the original vid from the same guy from a couple of months before
http://www.youtube.com/watch?v=7ly--g_yCyc )
Gimme a sec and I'll show you why it doesn't drop free.
Some weekend rocket scientist at ProMag put a 5.56x45 cartouche RIGHT above the mag catch. So if you press (but don't hold) the mag release it will catch in the cartouche and hold the mag in the weapon.
It took about 5 minutes to round the upper edge pff the cartouche and now the mag drops free.
The feed lips are about an 1/8th inch shorter on each side and if you're not usimg a stripper clip guide or a mag loader like a LULA, rounds will occasionally pop free during loading.
Right now I'm still experimenting but I'll keep everyone posted.