Source: ATF P 5300.11 · Curios or Relics List · Jan 1972 – Apr 20253,573 entries · 4 sections
The C&R RegisterA finding aid to the ATF Curios or Relics List, for Type 03 collectors
C&R · IV · 174

Oerlikon 20mm cannon, U.S.-made

Section IV: still an NFA firearm, also a curio or relic

Official wording

ATF P 5300.11 · APRIL 2025 EDITION · SECTION IV · VERBATIM · PDF P. 86 ↗

Oerlikon, 20mm Automatic Cannon, all variations mfd. in the U.S. prior to 1946.

What this entry requires

  • ATF REQUIRESMade or imported as stated: “mfd. in the U.S. prior to 1946”
  • ATF REQUIRESMade 1945 or earlier (ATF’s dates)ATF: “prior to 1946”
  • INFOStill an NFA firearm; only registered examples transfer, with ATF approval (26 U.S.C. 5812, 5861).

Editorial facts · Our research

Country
United States
Manufacturer
Various U.S. contractors
Type
Cannon
Action
Select-fire / auto
Caliber
20mm
Made
Before 1946²
Service
Military
Search listings ↗Check a specific gunReport an error ↗

Source

Official wording
ATF P 5300.11, April 2025 edition · Section IV · PDF p. 86 ↗ · ATF original ↗
Entries
1 line
Verbatim check
Checked against the PDF text before every release
Editorial facts
Confidence: Medium · Last revised 18 October 2026 (Evidence pass) · How we rate confidence
References
  1. Wikipedia, “Hudson Motor Car Company” ↗, years (estimate: partly supports it): 'On May 22, 1941, Hudson was given a contract for the Oerlikon 20 mm cannon... produced 33,201 Oerlikons for the United States Navy... until the end of the war' (contract year, not a dated first delivery); the end is also ATF's own limit (prior to 1946)
  2. Wikipedia, “Oerlikon 20 mm cannon” ↗, years: installed aboard United States Navy ships from 1942
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
2 changes · see below

Correction history

  1. Evidence passEditorial confidence: High → Medium. Years start rests on the May 1941 Hudson contract and 1942 USN installation, not a dated first production
  2. Evidence passYears: 1940–1945 → 1941–1945

All corrections · How corrections work

Historical context

Oerlikon 20mm cannon, U.S.-made

Image: Wikimedia Commons, “Oerlikon 20mm 2.jpg” by Fotograf/Photographe/Photographer: Jean-Michel Roche, CC BY-SA 3.0. Retrieved October 2026.

Summary: Wikipedia, “Oerlikon 20 mm cannon”. Text CC BY-SA 4.0.

FROM WIKIPEDIA

The Oerlikon 20 mm cannon is a series of autocannons based on an original German Becker Type M2 20 mm cannon design that appeared very early in World War I. Widely produced by Oerlikon Contraves and by others, its various models saw service with both Allied and Axis forces during World War II. Versions of the cannon were still in use in 2026.