.38 ACP
.38 ACP is a pistol cartridge or ammunition model.
Also recorded as .38 Auto.
In detail
It is associated with United States. The record gives 1900 as its date of establishment or first appearance.
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
“.38 ACP”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q2660322: .38 ACP
Consult the source