stick with usgi if you can find them
I don't even know what's USGI, seems like their are many knock offs. I do avoid the 5 & 10rd ones though, and try to avoid the 'last shot hold open' magazine followers.
Thanks for the info Robert, where are you finding the surplus mags? Gun shows and the EE are the only places I could think of.
Anyone else use the ones from Corwin arms? I was just thinking of ordering some.