Finnish M31

deputy125 · 06-10-2010, 05:33 PM

never knew this one existed or was available.............

seems over-built

http://www.jgsales.com/product_info.php ... a9f63a60e7

Bountyhunter · 06-10-2010, 05:40 PM

I like that. Only $20 for the 36 round magazines too.

44s Rock · 06-10-2010, 05:48 PM

Sure beats the price of a Thompson, are they any good?

Machinist · 06-10-2010, 05:51 PM

Those date back to the era of the Luger and the Thompson, lots of forgings and nice machining. No way today.

Bountyhunter · 06-10-2010, 05:58 PM

They look to be rebuilt guns. Is this the case? If they are dependable, they'd be great for the price.

Machinist · 06-10-2010, 06:03 PM

These were full auto with short barrels. They have used newly made parts to get semi-auto and legal length barrels.

No idea what the quality of the new parts is. These would be 9mm open bolt weapons, I think. They would have little interest for me. The original would be fun to play with if some one else was buying the ammo.

deputy125 · 06-10-2010, 06:07 PM

found a tad more about it here......

http://www.efour4ever.com/m31.htm

Quote:

Finland’s greatest assets of the 1939- 1940 Winter War were its tough skilled outdoorsman soldiers instilled with the belief that "One Finn is equal to ten Russians." Their weapon of choice, a sub-machine gun designed by Finland's native son, a self-educated genius, Aimo Johannes Lahti. Lahti designed and constructed many other weapons of note and of various types - from pistols to assault guns and an anti-tank rifle. The most famous is the m/1931 (M31) Suomi submachine gun - konepistooli. Imitation is the ultimate form of flattery. The Lahti M31 inspired the design of the German Bergmann MP34 and the Soviet PPD 1934G/38G and PPSh41 submachine guns. In the pantheon of modern gun designers, the prolific Lahti belongs as a peer with the likes of Hiram Maxim, John Browning and Mikhail Kalashnikov.

Expensive to manufacture and heavy, the m/1931 was lavishly made in the both the quality of the materials used and the excellence of the machining. The whole gun, the body and bolt were machined from solid metal. The machining detail was demandingly precise. Combat in the bitter Finnish winter requires a weapon which will function reliably in Finland's extreme artic conditions. Soldiers in field venerated their Suomi for its reliability. Its excellent construction enabled the gun to fire under any conditions without ever seeming to jam. To the shooter, the extra weight became a non-issue. The gun represented life to the Finn and death to the unfortunate Soviet.

With a rate of fire up to 900 rounds per minute, and with a massive 71-round drum magazine, the Suomi packed a lot of firepower. When first released, it established a record for rate of fire and held this record over a period of years. In spite of this high rate of fire, the M31 remained very easy to handle. Its weight and pistol caliber cartridge account for the stability. Add to this another paradox. The Suomi, a sub-machine gun, proved accurate beyond 100 meters, the standard range for this class of gun. Accurate fire reached the range of 300 meters. Such accuracy is due to the quality of manufacture and a long barrel of over 12 inches in length. Hot loads also contributed. Standard 9mm Parabellum performance of 365 meters/ second (1,200 f/s) was pushed upwards to 400 meter/second (1,310 f/s) with an 7.5 gram full metal jacket slug propelled by a white-hot powder load. This weapon's robust mechanism allowed use of ammunition that pushed the performance envelope to the maximum.

Machinist · 06-10-2010, 06:13 PM

It had a 12.6" barrel and weighed 11.3 lbs empty. It was made in and/or used in Finland, Denmark, Sweden, and Switzerland.

It was selective fire but fired from an open bolt.

sheepdog · 06-10-2010, 06:25 PM

...what is open bolt? heard of it often but don't know what it denotes????

Machinist · 06-10-2010, 06:31 PM

When you cock the weapon the bolt locks back. When you pull the trigger the bolt slams forward stripping and chambering a round and firing it as it closes. It is good on full auto weapons as it lets air cool the chamber and barrel and keeps the next round from cooking off. It also allows the momentum of the slide to hold the breech closed a moment longer and in some cases allows the firing pin to be a simple dimple on the face of the bolt.

For semi-auto it makes precision difficult as you have that heavy bolt slamming home before it fires and the trigger pull is often heavy. Some automatic rifle are set up to fire open bolt on full auto or closed bolt when set for semi auto.

44s Rock · 06-10-2010, 06:34 PM

Thanks Mac!

sheepdog · 06-10-2010, 06:35 PM

...so simple...and smart...thanks for the lesson...makes all kinda sense...only downside would be trash in the chamber/mag...a dust cover similar to the M16 would solve that...

Machinist · 06-10-2010, 06:40 PM

Full auto SMGs are easier and cheaper to make than semi-auto handguns. A couple of guys made a magazine fed automatic weapon in San Quentin prison and stole a laundry truck. It looked like an M-3 Greasegun. They made the ammo too but did not have primers so they made the cartridges electric ignition.

sheepdog · 06-10-2010, 06:41 PM

...shorted out on a battery for a flash? I'd love to know the details on that...it'd be a great book...

Machinist · 06-10-2010, 06:45 PM

The later version of the M-3 did away with the cocking linkage. They just drilled a finger hole in the side of the bolt and made the ejection hole longer so the GI could stick his finger in the bolt and pull it back. It had a hinged cover over the port. They welded or riveted a hook inside the cover that entered the finger hole of the bolt when it was back. Close the cover on a cocked bolt and instant safety! Flip up the cover and pull the trigger.

Machinist · 06-10-2010, 06:48 PM

The batteries were in the handle.

I remember a caseless .22 when I was a kid that used electric priming. Never caught on but it was advertised in the magazines.

I think when the F-15 was first being designed it was supposed to have a new 25mm rotary gun with caseless ammo and electric ignition. That was dropped for the old Vulcan cannon.

Machinist · 06-10-2010, 06:58 PM

They had a whole wall of guns made "inside" ranging from really crude zipguns to to that one. It shows how ridiculous it is to think they can keep guns from criminals. Even in high security prisons they can make them. What kind of society are these people dreaming of?

sheepdog · 06-10-2010, 07:39 PM

...that reminds me of the Gyrojet guns...wow....

Machinist · 06-10-2010, 07:50 PM

They were percussion fired but the hammer swung back and hit them on the nose, knocking the rocket back against the firing pin. The rocket recocked the hammer as it went forward.

sheepdog · 06-11-2010, 03:45 AM

...so, the end of this SA version's cycle will always be bolt open? that'd take some gettin' used to ...

06-10-2010, 05:33 PM	#1
deputy125 Senior Member Joined: Apr 2008 From: Texas Posts: 6,108	Finnish M31 never knew this one existed or was available............. seems over-built http://www.jgsales.com/product_info.php ... a9f63a60e7

06-10-2010, 05:40 PM	#2
Bountyhunter Site Founder Joined: Apr 2008 From: Allenstown, NH Posts: 25,463	Re: Finnish M31 I like that. Only $20 for the 36 round magazines too.

06-10-2010, 05:48 PM	#3
44s Rock Senior Member Joined: Jan 2009 From: Central WA. Posts: 5,968	Re: Finnish M31 Sure beats the price of a Thompson, are they any good?

06-10-2010, 05:51 PM	#4
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 Those date back to the era of the Luger and the Thompson, lots of forgings and nice machining. No way today.

06-10-2010, 05:58 PM	#5
Bountyhunter Site Founder Joined: Apr 2008 From: Allenstown, NH Posts: 25,463	Re: Finnish M31 They look to be rebuilt guns. Is this the case? If they are dependable, they'd be great for the price.

06-10-2010, 06:03 PM	#6
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 These were full auto with short barrels. They have used newly made parts to get semi-auto and legal length barrels. No idea what the quality of the new parts is. These would be 9mm open bolt weapons, I think. They would have little interest for me. The original would be fun to play with if some one else was buying the ammo.

06-10-2010, 06:13 PM	#8
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 It had a 12.6" barrel and weighed 11.3 lbs empty. It was made in and/or used in Finland, Denmark, Sweden, and Switzerland. It was selective fire but fired from an open bolt.

06-10-2010, 06:25 PM	#9
sheepdog Senior Member Joined: Apr 2008 From: Duncanville, Tx Posts: 22,117	Re: Finnish M31 ...what is open bolt? heard of it often but don't know what it denotes????

06-10-2010, 06:31 PM	#10
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 When you cock the weapon the bolt locks back. When you pull the trigger the bolt slams forward stripping and chambering a round and firing it as it closes. It is good on full auto weapons as it lets air cool the chamber and barrel and keeps the next round from cooking off. It also allows the momentum of the slide to hold the breech closed a moment longer and in some cases allows the firing pin to be a simple dimple on the face of the bolt. For semi-auto it makes precision difficult as you have that heavy bolt slamming home before it fires and the trigger pull is often heavy. Some automatic rifle are set up to fire open bolt on full auto or closed bolt when set for semi auto.

06-10-2010, 06:34 PM	#11
44s Rock Senior Member Joined: Jan 2009 From: Central WA. Posts: 5,968	Re: Finnish M31 Thanks Mac!

06-10-2010, 06:35 PM	#12
sheepdog Senior Member Joined: Apr 2008 From: Duncanville, Tx Posts: 22,117	Re: Finnish M31 ...so simple...and smart...thanks for the lesson...makes all kinda sense...only downside would be trash in the chamber/mag...a dust cover similar to the M16 would solve that...

06-10-2010, 06:40 PM	#13
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 Full auto SMGs are easier and cheaper to make than semi-auto handguns. A couple of guys made a magazine fed automatic weapon in San Quentin prison and stole a laundry truck. It looked like an M-3 Greasegun. They made the ammo too but did not have primers so they made the cartridges electric ignition.

06-10-2010, 06:41 PM	#14
sheepdog Senior Member Joined: Apr 2008 From: Duncanville, Tx Posts: 22,117	Re: Finnish M31 ...shorted out on a battery for a flash? I'd love to know the details on that...it'd be a great book...

06-10-2010, 06:45 PM	#15
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 The later version of the M-3 did away with the cocking linkage. They just drilled a finger hole in the side of the bolt and made the ejection hole longer so the GI could stick his finger in the bolt and pull it back. It had a hinged cover over the port. They welded or riveted a hook inside the cover that entered the finger hole of the bolt when it was back. Close the cover on a cocked bolt and instant safety! Flip up the cover and pull the trigger.

06-10-2010, 06:48 PM	#16
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 The batteries were in the handle. I remember a caseless .22 when I was a kid that used electric priming. Never caught on but it was advertised in the magazines. I think when the F-15 was first being designed it was supposed to have a new 25mm rotary gun with caseless ammo and electric ignition. That was dropped for the old Vulcan cannon.

06-10-2010, 06:58 PM	#17
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 They had a whole wall of guns made "inside" ranging from really crude zipguns to to that one. It shows how ridiculous it is to think they can keep guns from criminals. Even in high security prisons they can make them. What kind of society are these people dreaming of?

06-10-2010, 07:39 PM	#18
sheepdog Senior Member Joined: Apr 2008 From: Duncanville, Tx Posts: 22,117	Re: Finnish M31 ...that reminds me of the Gyrojet guns...wow....

06-10-2010, 07:50 PM	#19
Machinist Senior Member Joined: Feb 2009 From: McKinney, TX Posts: 6,131	Re: Finnish M31 They were percussion fired but the hammer swung back and hit them on the nose, knocking the rocket back against the firing pin. The rocket recocked the hammer as it went forward.

06-11-2010, 03:45 AM	#20
sheepdog Senior Member Joined: Apr 2008 From: Duncanville, Tx Posts: 22,117	Re: Finnish M31 ...so, the end of this SA version's cycle will always be bolt open? that'd take some gettin' used to ...

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