.22 extra long
.22 extra long is a rifle cartridge or pistol cartridge.
Overview
Obsolete rimfire rifle and handgun cartridge.
In detail
It is associated with United States.
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
“.22 extra long”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q969615: .22 extra long
Consult the source