And before someone brings it up: load 30 rounds in a 30 round mag, not 28, not 29...
Consider it brought-en: I load mine with 28. Sometime a fully loaded mag will be the cause of a FTF.. And I didn't learn that on the internet or read it in a magazine.
I would have to drop the mag, pop a couple of rounds out, and then put the weapon back into action. It happened enough times that I made it a rule to quit loading 30.
But, to each his own. A loaded mag, (no matter how loaded) is more useful than an unloaded mag.