This new ultra compact AR-15 magazine concept was spotted at TheFirearmBlog, one of their readers from Australia came up with the design that makes use of a “ribbon spring” which unfortunately isn’t shown in the CAD drawings as it is not yet patented. The design is unique in that it curves to the right and sits to the side of the lower receiver. While this makes the magazine more compact, unless it can fit more than 30 rounds in this configuration then I don’t really see the benefit. Also, it looks like it would be difficult to do quick mag changes.
