now that it's morning here in Aus, I just went and grabbed my 2 AICS style .308 mags outta the Safe... one is genuine AI, and the other is Accurate Mag... As mallrat said, slide the base off and it should become more clear. My Accurate Mag has a bronze coloured spring and a plastic spacer in the bottom, and the AI has a chrome coloured spring with no plastic spacer (though considering it came from the supplier with the base put on backwards, perhaps there was meant to be a spacer in there also)