Item: ONAC25241

Original Finnish WWII Suomi KP/-31 M31 9mm Display SMG with Live Barrel and Stick Magazine - Serial 40022

In stock

Regular price $1,295.00

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This item is a BATF-compliant, fully deactivated display machine gun and is not classified as a firearm under U.S. federal law. It has been permanently rendered incapable of discharging ammunition and cannot be converted to functional condition. As such, it does not require an FFL transfer, registration, or federal license for ownership or shipment within the United States. U.S. Sales Only: Due to legal restrictions, this item is available for sale and shipment within the United States only. It cannot be exported outside the U.S. under any circumstances. Purchasers are responsible for ensuring compliance with all federal, state, and local laws regarding the possession and display of inert or deactivated firearms in their jurisdiction.

  • Original Item: Only One Available. Offered in great condition is this lovely Finnish Suomi M-31 Display Submachine gun, built from all original parts on an original BATF compliant non-firing display receiver, making this a 100% legal display Sub-Machine gun. This receiver was created by using portions of the original torch cut receiver, including the barrel bushing, combined with some new made steel portions. It has properly had an over 50% section of the total length completely replaced entirely with solid steel bar stock (as required by BATF). Meaning a 1/2 length section of the display receiver is solid steel, making this totally legal to own without a license of any kind. Every part on this display gun is original WWII manufacture other than the replaced portions of the receiver.


    The display gun comes complete with an original stick magazine, which will be deactivated where required. The magazine well was cut through on this example, however the magazine release still functions great, and a magazine can be installed correctly, latching into place. The original deactivated bolt has been welded in the forward position as per BATF requirements.


    The rear sight and trigger are all still intact and movable, and the safety is present and can still move back and forth. The cocking handle is present with a functional spring, so it can be pulled back and will then snap forward. Also as a rare treat, the barrel jacket lock is functional, and the barrel jacket can still be relatively easily removed. This also allows the barrel to be removed, and it is is still LIVE, showing a bright bore with clear lands and grooves. It does show just a bit of wear to the lands, so it was in service for a time, but well cared for. Overall a very nice condition piece and very attractive!


    The sides of the sight are marked: SUOMI / Tikkakoski (left) and PATENT / 1932. (right), which are still fully legible. It is also stamped with the logo of the factory on the left side, a T inside a Triangle inside a Circle. The butt cap is stamped with serial number 40022, while the other numbers on the gun are all non-matching, indicating arsenal parts swapping. It also bears the [SA] mark of the Finnish Army (Suomen Armeija), which is present on rear sight base and the magazine. There are additional markings and proofs on various parts of the gun. The stock for this display gun is in great shape with lovely grain, showing wear and dents consistent with service, but no major damage or repairs. It has a reinforcement pin through the wrist, added as the stock is somewhat weak in the area.


    We have not had one of these in quite some time. A really great example with some great markings, a live barrel, and a stick magazine, ready to display!


    The Suomi KP/-31 (Suomi-konepistooli or "Submachine-gun Finland") was a submachine gun (SMG) of Finnish design used during World War II. It was a descendant of the M-22 prototype and the KP/-26 production model, which was revealed to the public in 1925. The Suomi-konepistooli KP/-31 is often abbreviated to Suomi KP or M31.


    The Suomi KP/-31 is regarded by many as one of the most successful submachine guns of WW2, also the soon developed 71-round drum magazine was later copied and adopted by the Soviets for their PPD-40 and PPSh-41 submachine guns. The accuracy of the Suomi was superior to that of the mass-produced PPSh-41, thanks in part to a noticeably longer barrel, with the same rate of fire and the equally large magazine capacity. The major disadvantage of the Suomi KP/-31 was its high production cost.


    The Suomi KP/-31 also incorporated a few new design features, including an arrangement whereby the spring was mounted inside the bolt in order to make the gun shorter. Its 50-round quad-column "Casket" box magazine was more reliable than the early 40-round "bullets loaded nose down" drum magazine, and similar applications were used on the Argentinian C-4 submachine gun and present-day 60-round 5.45x39mm AK-74 compatible magazines.


    The Suomi KP/-31 went into serial production in 1931 by Tikkakoski Oy and most of these weapons were bought by the Finnish Defense Forces. The Finnish Defense Forces were equipped with about 4000 Suomi KP/-31 submachine guns when the Winter War started. During the course of the war, the design was altered with the addition of a muzzle brake, which increased the submachine gun's overall length by 55 mm. The revised version was designated KP/-31 SJR (suujarru, or "muzzle brake"). Aimo Lahti was displeased with this revision, believing that it decreased muzzle velocity and reduced the weapon's reliability, and even sought in vain to have the muzzle brake's designer court-martialed. Ultimately, roughly half of the KP/-31s in Finnish service were of the SJR version. Initially the KP/-31 was issued as a substitute for a light machine gun, and proved inadequate in this role. Instead, soldiers learned by trial and error how to use submachine guns to the best effect.


    By the time of the Continuation War, Finnish doctrine had been altered to include both a KP/-31 and a light machine gun (usually a captured Degtyaryov DP) in every infantry squad, and by 1943 this had been expanded to two KP/-31s per squad. KP/-31 production continued with the intention of adding a third submachine gun to each squad, but this plan was shelved in 1944 when the Continuation War ended.


    The Suomi KP was also manufactured under license in Sweden, Denmark, and Switzerland, where it was known as the Hispano-Suiza MP43/44.


  • This product is not available for shipping in US state(s): Washington, and New Jersey

    This product is not available for international shipping.
  • Not eligible for payment with Paypal or Amazon

Frequently Asked Questions

Yes, this item is a BATF-compliant, fully deactivated display machine gun and is not classified as a firearm under U.S. federal law. It has been permanently rendered incapable of discharging ammunition and cannot be converted to functional condition. As such, it does not require an FFL transfer, registration, or federal license for ownership or shipment within the United States. U.S. Sales Only: Due to legal restrictions, this item is available for sale and shipment within the United States only. It cannot be exported outside the U.S. under any circumstances. Purchasers are responsible for ensuring compliance with all federal, state, and local laws regarding the possession and display of inert or deactivated firearms in their jurisdiction.

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