In the picture the 3D printed replicas are in the lower row. From the left, they are 1,3,4 and 5. The typical 3D printed striations are easily visible on #4. Australia has, in many ways, some of the most extreme gun regulations in the world. By jumping through a great many hoops, and carefully filling out the right forms over several months, you can own and use a significant number of firearms. The regulations are a wish list of most of those proposed by gun hating activists from around the world. The were rushed through the Australian political machine...