BL 18 inch Mk I gun
BL 18 inch Mk I gun is a naval artillery or rifled breech loader.
Overview
British naval artillery.
In detail
It is associated with United Kingdom of Great Britain and Ireland.
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
“BL 18-inch Mk I naval gun”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q4835889: BL 18 inch Mk I gun
Consult the source