Allied industry could sustain mixed French ammunition

How would Britain and France in exile cope with their different ammunition types?

Through custom production and retained French support, drawing on British yards plus Canadian and American industry where necessary.

Supporting different French and British ammunition types would require custom work. British yards already had relevant industrial capacity and some experience with such work. Canadian and American industry could also contribute. A departure by the entire French Navy would bring additional French infrastructure and industry, making this a different support problem from the historical Free French situation.