Pistol: Lahti m/40

Swedish Pistol Lahti m-40 left

Pistol Pistol m/40 “Lahti” Manufacturer Husqvarna Vapenfabriks
Cartridge 9x19mm Overall Length 9.6″
Action Short Recoil Barrel Length 4.2″
Magazine 8 rounds vertical Weight 2.64 lbs

 

 

 

 

 

Sweden’s delay to recognize the oncoming war sent them scrambling to their neighbor Finland for a sidearm.  While they copied the best cold weather sidearm of the time, local production had a few issues to overcome.


During the interwar period, the Swedish government was convinced, like many other neutral nations, that there would never be another Great War.  It was not until very late in the 1930′s they realized what was coming.  At the time their military was primarily armed with a Browning 1903 licensed copy.  The Swedish m/1907 was a WWI leftover being produced domestically by Husqvarna.  It chambered the 9x20mm semi-rimmed cartridge with somewhat lackluster ballistics and stopping power.  The military wished to move to the 9x19mm round common in Europe then and now.  The aim was to standardize their sidearms on an acceptable submachine gun cartridge.  At first they meant to adopt the German made Walther HP, a pistol that became the P38, but sufficient numbers were not available for import as the war began.  Over 8,000 Swedish volunteers served in the Finnish Winter War and as they returned so did a high opinion of the Finnish Lahti L-35 pistol.  The 9x19mm pistol was a good fit with a fine reputation and so a production license was acquired and Husqvarna Vapenfabriks began production in 1942 with a total run around 80,000.

Swedish Pistol Lahti m-40 top

The Lahti pistols feature the steep grip angles of the Luger and Nambu pistols, consequently sharing their natural point of aim and minimizing the strain of recoil. Lahti actions are a clear descendent of the Bergmann-Bayard M1910, using roughly the same breech-block system.  All variations chamber the same 9x19mm cartridge. Their eight round capacity detachable magazine is retained by a heel catch in the European standard of the time.  The sights, while nothing fancy from a modern standpoint, are excellent for the period.  The front sight is very tall and the rear notch deep, making for a very legible sight picture.  There is a provision at the rear of the frame for a detachable stock but this was rarely used.

The Lahti is loaded by inserting a removable magazine and pulling back on the exposed rear of the bolt and releasing.  As the bolt is drawn back it cocks the internal hammer back and as it returns forward strips a round from the magazine and chambers it.  When the trigger is pulled the hammer strikes the rear of the firing pin in the of the bolt, forcing it into the primer of the chambered cartridge and discharging the weapon.  The recoil force drives the bolt and mantle back, initially locked together.  This is achieved by a yoke that fits a notch on the top of the bolt (the locking block).  When lowered the locking block fixes the bolt to the mantle and therefore the barrel.  As the mantle travels backwards the locking block’s guide lugs run down grooves set inside the frame.  After several millimeters of travel the grooves direct the locking block upwards, releasing the bolt which carries on after the mantle is stopped by impacting the frame.  As the bolt travels rearward the embedded extractor pulls the spent casing free of the chamber and into the ejector, throwing it out to the right.  The bolt is returned forward by the recoil spring, again stripping off a fresh round from the magazine and shoving the mantle forward.  The locking block is guided forward and down, locking the action back up and readying the gun to be fired again.

Swedish-Pistol-Lahti-m-40

At low temperatures combustion in the cartridge is weakened.  Additionally, icy conditions in Scandinavia might freeze the action shut.  In order to guarantee proper function the Lahti was fitted with an accelerator component.  When the mantle stops it slams a semi-circular piece of metal against the inside of the frame.  This piece pivots as it slides over a pin in the mantle and the other side strikes the front of the bolt violently.  This assures that the bolt will have enough kinetic force to be driven fully rearward, completing ejection of the spent casing and on the return picking up a new round with enough force to chamber properly.

Lahti m/40 pistols can be divided into four variations based on the mantle used.  Type I is nearly identical to the Finnish Lahti.  Most notably it had a loaded chamber indicator and a notch along the mantle in front of the accelerator.  Unlike Finland, Sweden skimped on the steel for their mantles and used molybdenum to make up for it.  Cracks began to show and so the loaded chamber indicators were ground off and welded up.  If you see the remnants of the indicator, know that your gun is still considered a first type.  Type II pistols were created without the indicator and had three holes setup for the accelerator.  Type III ditched the notch in front of the accelerator and has a reinforcing ridge to help strengthen the mantle.  You can see this ridge as the raised metal in front of the ejector.  Type IV mantles were made by Carl Gustaf postwar.  These are made much stronger than the earlier production and have slightly more reinforcing material at the rear tabs.  They lack the Husqvarna stamp on the left side.

Swedish Pistol Lahti m-40 openThe mantle variations are the most prominent but other adjustments were made during production.  Minor changes to soften the internal angles were common and need not be discussed in detail.  Perhaps more telling is that the barrels were changed to include an external nut at the base to ease removal and reassembly.  At the same time the stepped front sight was replaced with a simpler boxed base one.  The original black bakelite grips turned red as materials shuffled during the war.  Pistols marked with a “D” prefix were used by the Danish police.

Standard accessories include a leather holster with flap which seats two spare magazines, a cleaning rod, and a tool to assist reloading.  Because of concerns over proper feeding of rounds through such a steep magazine well, the Lahti pistol has an extremely strong magazine spring.  Hand loading is a tremendous effort and so the tool was made and included.  You simply slip the tool over the magazine and use it to depress the magazine spring before inserting the ammunition.

Lahti pistols are not entirely common and carry a good value for collectors.  We would certainly recommend acquiring such a piece if given the opportunity as they are an incredible cold weather pistol with a good history to tell.  Be wary however and make sure you look the gun over well before purchasing.  Go ahead and memorize the simple field stripping instructions and ask any seller to let you inspect the inside of the frame and mantle for cracking.  This is common because of a high powered Swedish SMG cartridge in 9x19mm finding its way into many pistols due to carelessness at the range.  As always a visit to the gunsmith is recommended when shooting these old firearms but more so with the Lahti given its history of accidental abuse on its components.

Swedish Pistol Lahti m-40 POV 8

 


 

7 Responses to “Pistol: Lahti m/40”

  1. Nagao says:

    This article was made possible with help from East Coast Guns of Summerville, SC. They were kind enough to become our first gun donor! Please thank them for us when you stop by.

    http://www.eastcoastgunshop.com/

  2. Sean says:

    Great article! That’s an incredibly interesting gun, the changes made for the cold weather are fascinating.

  3. PCShogun says:

    Great article and I love the animation. It clearly shows the accelerator component and its operation.

  4. marc says:

    Do you know of a serial number index for these pistols? I am trying to establish an age on one.

  5. Skeezix says:

    Are you sure about the “D” series guns being for Danish police? I always thought the “Rplt” guns were the ones used by Danish police, and heard that the so-called “D”: series guns were more or less for commercial sales after WWII.

    • Othais says:

      I’ve learned to be sure of nothing. Let me know if you remember the source and I can double check. We leave the comments open for just this peer-review reason!

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