> The obstacles the U.S. faces in ramping up production can be seen at the Scranton plant.

> The factory — built for the Delaware, Lackawanna and Western Railroad just after 1900, when the city was a rising coal and railroad powerhouse — has produced large-caliber ammunition for the military going back to the Korean War.

> But the buildings are on the National Historic Registry of Historic Places, limiting how the Army can alter the structures.