Ever since President Barack Obama launched Operation Inherent Resolve against ISIS in Iraq and Syria in 2014, U.S. military personnel and their regional allies have increasingly been forced to stare down the barrels of their own weapons. An exhaustive new investigation of ISIS weapons caches details just how many small arms and ammo caches are falling into terrorist hands — and highlights the Department of Defense’s cavalier attitude towards funneling weapons there, helping to fuel what investigators called “[an] industrial revolution of terrorism.”