Gun enthusiasts group Defense Distributed has successfully produced a 30-round clip using a 3D printer.
 
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The printed mag was displayed in an AR series assault rifle, but it's worth noting that the AR series uses standard NATO STANAG magazines, which means the printed magazine is compatible with a wide range of 5.56x45mm weapons used around the world.
 
The implications of using 3D printers to churn out rifle magazines are profound. One of the key proposals in the gun control debate is a ban on high capacity assault rifle magazines, which could now be circumvented by anyone with access to a decent 3D printer and a few CAD files. Such a ban would be practically impossible to enforce. -TechEye