In Depth: Gun-Parts Maker Faces a Decade in Prison Over Tiny Nut

China has some of the strictest gun controls in the world — just buying the wrong toy replica can lead to life imprisonment. The latest reminder of this unforgiving framework centers around a tiny nut known as an “iron head.” Used to affix certain parts to the body of a weapon, they can be considered components for both toy and real firearms. And it’s this determination that stands between freedom and a decade behind bars for Ma Xiaoqiang.