From The Atlantic:

Gun policy is a famously impossible problem in contemporary America. Any ideas that might actually reduce gun violence are stymied by political division or struck down by courts. Gun buybacks are the only form of gun control that both gun opponents and gun supporters like. There’s just one problem: They don’t work. Scholars have tried for years to quantify the benefit of buybacks, and they’ve consistently found little empirical evidence that they do much of anything to reduce gun violence at all.