Tank manufacture (Chrysler). Test is thorough at the proving grounds adjoining the Chrysler tank arsenal near Detroit. These are twenty-eight ton M-3 tanks, the steel monster which will make our mechanized forces the equal of any in the world in tank warfare. The lower of the two gun barrels is that of a 75 mm. gun, the upper of a 37 mm. anti-aircraft gun, both standard equipment on these tanks. In addition, four machine guns are mounted on each M-3