I photographed these examples of the US Navy’s 40mm Bofors Anti Aircraft Guns (single, twin, quad) on display at Patriots Point and Pensacola, and a single Bofors unit at the Museum of Flight.
The US Army also used the 40mm Bofors, and I was able to photograph Towed 40mm Anti-Aircraft Gun examples at Dubois and the Yuma Proving Grounds.