My uncle, who worked for Chrysler for many decades, had four small volumes published by Chrysler explaining what that corporation did during World War 2. It has been more than 20 years since I read the same. However, I think I remember something about these guns. They were the Bofors gun, a Swedish design licensed and used by all the belligerents of that war. They were a 40 mm, rapid fire, repeating anti-aircraft canon which required many hours of work by highly skilled machinists to produce all the intricate parts of the repeating mechanism.

Chrysler received a large contract from the US Army to produce approximately 40,000 guns, each with a spare barrel and mounted singly on a trailer (probably not the correct term for this mounting system). After producing about 30,000 guns, the contract was cancelled in 1944 because the guns were not wearing-out as expected. The barrels in particular lasted for many more rounds than were originally specified.

Chrysler also sped up delivery of the guns by using their newly developed powdered metal technology for fabricating the intricate parts, which avoided the necessity of time consuming machining. Early on, one part of the automatic mechanism failed after too few rounds were fired. The engineers solved this problem not by beefing up the part to make it stronger, but by thinning it to allow it to be more flexible. Ingenious!