Replace your stock magazine lip for your WA M4 with this steel magazine lip from G&P for a more consistent feed. A side-effect of installing this magazine lip actually helps reduce jams from occurring!
Works perfectly with gbb mags used with golden eagle gbbr’s, pretty much the only place I could find them too. Dimensions are slightly different but that’s barely noticeable, they’re also stronger than the feed lips that come with the magazines. Also the shipping was pretty fast for having to be shipped overseas.