Thank you for posting this drawing. Dominion Rubber Munitions Ltd (a subsidiary of United States Rubber Co.) was contracted to start production of .5" Vickers in late 1942 and they established a factory at Cap de la Madeleine (Three Rivers/Trois Riviere). The manufacturing equipment was provided by Dominion Arsenal. 20mm Oerlikon replaced the .5" Vickers in 1944 and 20mm was manufactured to the end of the war.
Aluminum cased 20mm Oerlikon can be found dated both 1944 and 1945. I have a complete draw set and components from another.
Here is a picture of a draw set (for space, I’ve left out the annealing and trimming steps).
This is a factory dummy (no primer) and fired case. The dummy shows signs of hardness testing around the circumference of the base.
Headstamps of the dummy, fired case and another piece showing the different overstamps that can be found (01, 14, E). The fired case is dated 1945.
As for other calibers, this 20mm HS round is attributed to Dominion Arsenal (I don’t know the dates). I think that the side of the case from which the anodizing was removed was for hardness testing.