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 · 218

SIG MKPO carbine

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. 88 ↗

Swiss (Societe Industrielle Suisse) MKPO carbines, cal. 7.65mm, with barrels less than 16".

ATF lists cal. 7.65mm; this is the 7.65mm Parabellum cartridge.

What this entry requires

  • ATF REQUIRESConfigured as the ATF wording states: “with barrels less than 16"”
  • INFOATF states no date; production was about 1933–1937.
  • INFOStill an NFA firearm; only registered examples transfer, with ATF approval (26 U.S.C. 5812, 5861).

Editorial facts · Our research

Country
Switzerland
Manufacturer
Schweizerische Industrie-Gesellschaft (SIG)³
Type
Rifle
Action
Other
Caliber
7.65mm Parabellum²
Made
c. 1933–1937production; ATF states no date¹
Service
Commercial
Search listings ↗Check a specific gunReport an error ↗

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: Medium · Last revised 17 October 2026 (Data-trust review) · How we rate confidence
References
  1. Wikipedia, “SIG MKMO” ↗, years: MKMO produced by SIG at Neuhausen from 1933 to 1937; MKPO is the short-barrel police variant
  2. Wikipedia, “SIG MKMO” ↗, calibers: chamberings include 7.65×21mm Parabellum
  3. Wikipedia, “SIG MKMO” ↗, maker: Schweizerische Industrie-Gesellschaft (SIG)
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

  1. Data-trust reviewEditorial confidence: Low → Medium. Re-rated after supporting references were added or re-checked.

All corrections · How corrections work

Historical context

SIG MKMO (base model shown for SIG MKPO carbine)
Shown: a SIG MKMS, not this MKPO police carbine.

Image: Wikimedia Commons, “Mkmsswedish.png” by Armémuseum (The Swedish Army Museum), CC BY-SA 3.0. Retrieved October 2026.

Summary: Wikipedia, “SIG MKMO”. Text CC BY-SA 4.0.

FROM WIKIPEDIA

The SIG MKMO is a submachine gun produced by Schweizerische Industrie Gesellschaft (SIG) company in Neuhausen from 1933 to 1937. The MKMO – M = Maschinen, K = Karabiner M = Militär, O = Oben – was designed for the military and to increase firepower it had a larger-capacity magazine as well as a longer barrel. Only 1,228 of these guns were produced. It saw limited adoption by Swiss police departments and the Swiss Guard at the Vatican. Finland purchased 282 of the MKMS variant, which were used by the home guard, supply units and coastal defense forces in the Continuation War.