M621 cannon
M621 cannon is an autocannon or artillery model.
Also recorded as M621.
Overview
20 mm automatic cannon.
In detail
It is associated with France.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“M621 cannon”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q3272564: M621 cannon
Consult the source