I got a couple windowed magpul 30 rd. magazines a few days ago. Upon loading, I noticed that one of them had a defect (purely cosmetic) that partially covered one of the windows, Looked like paint overspray or some such. When I tried to return it to my dealer, they told me to call Magpul.
So I'm thinking "Great, here comes the runaround".
Wrong, I call Magpul and they promptly get my info to send me a new mag, and even cover postage for return of the bad one. Can't ask for much more than that.