Outside the Federal Ammunition plant in Anoka, Minnesota, stand a few tall silos. But they don’t hold grain. Inside are tens of millions of tiny plastic pellets, which will be heated and stretched into plastic shotgun hulls. Across the campus, molten lead is dropped into water to form pellets, then sorted for roundness and screened for size. The hulls are pumped above a sprawling factory floor in a series of air-pressured tubes, then mated to brass, primed, loaded in a new top-secret loader, cha