America’s defense industrial base has a metal parts problem. Since the 1980s, the U.S. has lost roughly 1,600 foundries (~50% of the domestic base) and 4,400 metal casting facilities (~75% of the base). Critical cast and forged alloys now face 70–80 week lead times. The 155mm artillery production effort shows what this erosion looks like in practice. The Army has invested $4.5B since 2022 with the goal of producing 100,000 rounds per month. As of March 2026, output was 36,000 rounds per month. Much of the constraint sits upstream in qualified projectile metal parts production. A ~$500M Texas facility designed to produce 30,000 parts per month had yet to produce a single contract-compliant part as of March 2026. That same supply chain weakness affects missile production, propulsion, drones, shipbuilding, and other critical systems. These programs depend on the ability to produce complex metal components at speed and scale. Rebuilding the industrial base requires more than new factories. It requires qualified domestic capacity to cast, forge, machine, inspect, and produce complex metal parts – plus flexible manufacturing capacity that can shift across programs as demand changes. This is the defense industrial base challenge.