I just bought a POF 308 with a serial number starting with 09-xxxx. The PMAG 20 LR/SR GEN M3 are very rough going in. I remember reading somewhere that if your serial number starts with a 12-xxx and later that you need the Gen 2. Anyone else have a problem like this or know where I can get some Gen 2 mags? I do have a DPMS metal mag that seems to work fine.