C&R · IV · 131
Type 99 20mm Oerlikon aircraft cannon
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. 85 ↗
Japanese, cal. 20mm Oerlikon Model 99, Machineguns/Cannons.
What this entry requires
- INFOATF states no date; production was about 1937–1945.
- INFOStill an NFA firearm; only registered examples transfer, with ATF approval (26 U.S.C. 5812, 5861).
Editorial facts · Our research
- Country
JapanBasis: the ATF wording - Manufacturer
- Dai-Nippon Heiki; Toyokawa & Tagajō Naval ArsenalsBasis: outside reference ¹
- Type
- MachinegunBasis: the ATF wording
- Action
- Select-fire / autoBasis: the ATF wording
- Caliber
- 20mmBasis: the ATF wording
- Made
- 1937–1945production; ATF states no dateBasis: outside reference ²
- Service
- Military
Source
- Official wording
- ATF P 5300.11, April 2025 edition · Section IV · PDF p. 85 ↗ · 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, “九九式二〇ミリ機銃” ↗, maker: licence-built Oerlikon FF/FFL: knock-down production at Dai-Nippon Heiki (then Tomioka Heiki) from summer 1937, licence production from July 1938; later also produced at the Toyokawa and Tagajō Naval Arsenals
- 2. Wikipedia, “九九式二〇ミリ機銃” ↗, years: production from summer 1937 (renamed Type 99 in 1941); Mark 2 from spring 1943; the faster-firing Mark 2 Model 4, developed autumn 1944 – winter 1945, reached mass production (en: adopted by the IJN 1939)
- 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
- Evidence passYears: 1939–1945 → 1937–1945. Japanese Wikipedia: production began summer 1937 (1939 = IJN adoption)
- Evidence passMaker: Japanese Navy arsenals → Dai-Nippon Heiki; Toyokawa & Tagajō Naval Arsenals. Japanese Wikipedia: built by Dai-Nippon Heiki, later also at the two naval arsenals
Historical context
Image: Wikimedia Commons, “Navy Type 99-1 & 99-2.JPG” by US gov. employee, Public domain. Retrieved October 2026.
Summary: Wikipedia, “Type 99 cannon”. Text CC BY-SA 4.0.
FROM WIKIPEDIA
The Type 99 Mark 1 machine gun and Type 99 Mark 2 machine gun were Japanese versions of the Oerlikon FF and Oerlikon FFL autocannons respectively. They were adopted by the Imperial Japanese Navy (IJN) in 1939 and served as their standard aircraft autocannon during World War II.