Ok, before I knew better(about late 2007) I got 5 stainless cproducts mags. I want to test them to see whether or not I can trust them. I’ve ran a mag or two through a few of them (I use my pmags for most shooting) and they’ve worked fine, but I can’t see that as much of a diffinitive test. What would you guys reccomend as a good test to see if a mag should be reliable?
Make sure they lock into the mag well, drop free, engage the bolt stop and that the follower doesn’t bind. However, nothing can replace test firing.
Step One: Visually inspect magazine
Step Two: Load magazine
Step Three: Insert magazine into weapon
Step Four: Charge Weapon
Step Five: Remove Safety
Step Six: Fire weapon over and over, (aka: mag dunp)
Step Seven: Grin 
If the mag fails to perform, place at 50-yard berm and repeat steps 1-7… 
I’ve learned that if you’re running Pmags, or the USGI’s with Magpul followers the amount of live test rounds fired is minimized. They’re just that good if you’re running a quality rifle that is in spec. For me a I run 3 mags worth of my SHTF ammo and call it good if there are zero defects. I wish I could say the same before I trust my 1911 CCW Mags, although I pretty much trust Tripp’s Cobra Mags right out of the box now. Almost!
The other issues mentioned are also a pre-requisite.