United Defense UD M42
Official wording
United Defense Supply Corporation, Model U.D. 42, cal. 9mm Parabellum, submachinegun, as mfd. by Marlin Firearms Company, New Haven, CT.
What this entry requires
- ATF REQUIRESMade or imported as stated: “as mfd. by Marlin Firearms Company”
- INFOATF states no date; production was about 1942–1943.
- INFOStill an NFA firearm; only registered examples transfer, with ATF approval (26 U.S.C. 5812, 5861).
Editorial facts · Our research
- Country
United StatesBasis: outside reference ¹- Manufacturer
- Marlin Firearms Co., New Haven, CTBasis: the ATF wording
- Type
- SMGBasis: the ATF wording
- Action
- Select-fire / autoBasis: the ATF wording
- Caliber
- 9mm ParabellumBasis: the ATF wording
- Made
- 1942–1943production; ATF states no dateBasis: outside reference ²
- Service
- Military
Source
- Official wording
- ATF P 5300.11, April 2025 edition · Section IV · PDF p. 88 ↗ · ATF original ↗
- Entries
- 1 line
- Verbatim check
- Checked against the PDF text before every release
- Editorial facts
- Confidence: High · Last revised 18 October 2026 (Evidence pass) · How we rate confidence
- References
- 1. Wikipedia, “United Defense M42” ↗, country: infobox origin United States
- 2. Wikipedia, “United Defense M42” ↗, years: infobox production date 1942–1943 (15,000 made)
- Fact tags
- ATF the ATF wording states it.
- REF ¹ an outside reference supports it; the number points to the list of references.
- ESTIMATE an approximate or indirect reading, for example the production range of the base model.
- NO CITATION we haven’t attached a reference for this fact; it’s our editorial reading, not ATF’s.
- Source checked
- 20 October 2026: ATF’s page still lists the April 2025 edition
- Corrections
- 1 change · see below
Correction history
- Evidence passYears: 1942–1945 → 1942–1943. Wikipedia infobox gives production 1942–1943
Historical context
Image: Wikimedia Commons, “United Defence M42.jpg” by Atirador, CC BY-SA 3.0. Retrieved October 2026.
Summary: Wikipedia, “United Defense M42”. Text CC BY-SA 4.0.
FROM WIKIPEDIA
The United Defense M42, sometimes known as the Marlin for the company that did the actual manufacturing, was an American submachine gun used during World War II. It was produced from 1942 to 1943 by United Defense Supply Corp. for possible issue as a replacement for the Thompson submachine gun and was used by Office of Strategic Services (OSS) agents. However, its usage was limited, and the Thompson continued to see service until the end of the war, alongside the M3 submachine gun, which was designed around the same time as the M42.