On my Honey (Stuart turretless) tank we used to use the Thompson Sub Machine Gun (Tommygun) as a weapon for nightime guard duty as this was considered more effective than our Smith & Wesson pistols.

I never ever fired it in anger but was able to get some practice in when I was at the RAC Training Depot in Rieti (Italy).

I only ever used the 30 Browning on one occasion when I nearly killed our driver !

ps
I must now go and find the link to the story !
Found it !
BBC - WW2 People's War - Diary Entries 11th April 1945
I see the same story mentions my Tank Commander using a Tommy Gun

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During the period October 1942 to January 1947 my wartime "Cook's Tour" took me to the following places:
North Africa, Sicily, Italy, Austria, Egypt & Germany.
My units were the: 49th Light Ack Ack Rgt.RA and
The 4th Queen's Own Hussars.