So far all mags I have tried work in my rifles but I’m glad I learned something from this post. Didn’t know about that little P Mag trick.
I just did it like 10 minutes ago and it worked like a charm.
Before mod: http://www.youtube.com/watch?v=f04ot8B_zu0
After mod: http://www.youtube.com/watch?v=FGoSlY6NX8g
I had 2 rev ms that wouldn’t drop free, worked on them too.
There is some interesting reading on tolerance stacking HERE if you have the time.