RML 12 inch 25 ton gun
RML 12 inch 25 ton gun is a rifled muzzle loader or coastal artillery weapon.
Overview
British naval/coastal defence artillery.
In detail
It is associated with United Kingdom.
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
“RML 12-inch 25-ton gun”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q1307896: RML 12 inch 25 ton gun
Consult the source