Ok, first off all WTF are you guys talking about?
1. PMAG's will accept 30 rounds no problem. I have 75 loaded ones in my safe.
2. Downloading magazines does nothing for spring life. Springs are worn by the compression and decompression of the spring which causes fatigue.
3. If you are loading 75gr. or 77gr. ammo you may have a few issues if you don't make sure that the rounds are seated properly. I have experienced this on a few occassions.
4. If you don't know what you are talking about don't come in here posting speculative and silly bullshit.

