[Stellan Bojerud (RIP)]

Slowly the puzzle gets more and more complete.

Otis Elelevator Co and Fensome Elevator Co amalgamated in 1905. In 1940 the Government built a gun factory at Otis Fensom Elevator Co establishments in Hamilton, Ontario. Some 3.000 workers were employed.

The first gun was delivered in August 1941.

In 1946 the gun factory was bought by Studebaker. In 1969 bought back by Otis and used as a warehouse. Closed 1987.

Here a 40 mm Bofors on MK II carriage training before D-Day.

I think someone could identify the unit by blue-red sign with white 73.