This question comes up from time to time, and someone always says to avoid everything but USGI. They don't usually say why, however, so I'll tell you my experience. I bought some of the cheap M14 mags from Cheaper than Dirt thinking, "How bad can they be?" Well, the lock block was pressed into the edge of the mag instead of a rectangle of metal being welded on as is done on the USGI mags. Result, the mag slipped down an inch after three or four shots, and the no round would strip from the mag until I pushed it back in.
As others have said, the Coles Distributing mags are universally liked, and at least a few folks over at BattleRifles.com have had good experiences with the ones that Ammoman is selling.
Hopefully, there will be reasonably priced M14 mags after the ban expires, at least for those of you, unlike me, who live in relatively free states. Believe me, as soon as I can convince my wife to leave, we're outa here.
Then again, a brand new Springfield Armory 10-rounder costs $35. I doubt the 20-round mags from them will be less than that.
