Finnish KP/31

[broher]

So my question is can i make this gun from Thompson M1A1 or AGM MP40?

[broher]

heres a link to wikipedia page that has intel of this gun
en.wikipedia.org/wiki/Suomi_M-31_SMG

[YankeeDiv26]

I don't think this is a question anybody can give you a real yes or no for. Technically anything's possible, its just a matter of many many factors to see if it can be realistically done. Take some measurements, do some research, and be sure you are capable of doing it before you try.

[CharleyNovember]

I've got one of those Sumi's as a torch cut kit with the drum mag. Don't ask me why I have it but I do.

[Dog]

Well, Thompson AEG has the motor in a rear grip right? Finnish KP/31 doesn't have one, so you have to make big changes.
MP-40 is something I have been studying more closely and the basic structure seems OK. However the internals (mechbox,hopup unit) are too long for a KP/31. The place for a magazine goes too much forward. So you should cut the box shorter and replace the trigger about 2 inches forward.

Since the Russian PPSh-41 is a copy of Finnish KP/31, the solution Gryphon has used for his PPSh-41 Prototype, sound good.



This is some kind of a holy grail for Finnish ww2 airsofters. I have heard that someone has done one, but I haven't seen any photos.

[broher]

I just searched the forums and found one poll where someone had made PPSH-41 by molding the parts and carved the wooden parts. Could that be made? If i would mold the outher barrel and the recever and carve the wooden parts?

[schmitty]

Parts kits are available for those quite cheap I believe. It's dimensions look very similar to a PPSH-41 so it looks possible to me (I made a PPSH41 from a parts kit using its original stock). I say go for it!!

Schmitty

[Dog]

Here is another type of magazine, so called coffin magazine. It was poorer in quality and had some feeding issues, but was still quite common.



This fellow is corporal Viljam Pylkäs who is reputed to kill one company (about 80 Russians) in one skirmish with his KP/31. Another private was all along filling the drum magazines for him.

[binarypunisher]

Its hard to see from the photo...but is that a quad stack magazine?

[Dog]

Here are the both mag types:

And here's the source: www.jaegerplatoon.net/MACHINEPISTOLS1.htm

[valtteri]

If I remember correctly the one Finn that did the KP/31 used some gearbox with vertically protruding motor, that he refitted horizontally. He used a deact real steel gun with apparently all outer parts, I dunno.

Then there's that Jap guy who made a KP/31 from scratch. Dimensionwise, that is obviously easy, and the end result looked good in pictures.

Deact KP/31s are well available in Finland. The thing to remember with these is that it is illegal to separate the barrel jacket and receiver, which is necessary if you want to use the deact as a base.

Barrel jackets, sights etc are well available. I think the best way to go is to fabricate your own stock, receiver and barrel and use most of the rest from real steel spare parts, which you can buy license-free from Finnish gun shops and gun shows.

If what I said above does not get you going, forget the project..

[ukkolziasd]

I have handled the custom airsoft KP/31. Boy, did he modify the box! The gears were placed in different spots and the motor was horzontally aligned. If I remember correctly, it was version 2 or 3. Of course if some other gearbox would fit with less modification...

If you are not going to make the parts yourself, be prepared for some hard work, as KP/31 has some parts overdone in material strength and thickness. It's sort of a Finnish mentality in gun designing. And combat webbing designing. Hell, in about everything. ;D

Anyway, if you take on the project, good luck!