Identify MP40

*** Originally posted by metradio ***


I have recently managed to aquire a blank firing replica MP40, but am unable to identify the maker, as the only markings are on top of the receiver:

MP40
72
0476

The firing pin is in the breech and the bolt will accept a 9mm round..

Mike

*** Originally posted by claymore ***


I think that the blank firing MP40 will be a converted MGC all metal version which would be the only model that could take the pressure of a blank. MGC 68 i think it is, Mark will most certainly but able to confirm or correct this but sure i am right.

*** Originally posted by metradio ***


Think I might have described it wrongly, the firing pin is in the breech facing backwards, so it probably fires plug fire blanks, and the bolt is machined to feed 9mm brass.. Yes it is all metal..

*** Originally posted by mark ***


Hi metradio,

Again, welcome to the forums!

What it sounds like you have MP40 wise, is an Nakata made MP40 these are typically made of zinc alloys and some pressed steel they are convertable into 9mm blank firing due to their heavy zinc construction and their removable "barrel bushing"

I have never personally handled one of these Nakatas but they look good and they are collectable..

They do have a slight problem area, the front sight hood is cast out of zinc and they are fragile when knocked about...So, be carefull with the front sight hood or replace it with a pressed steel assembly...

*** Originally posted by metradio ***


Thanks for the info Mark, I note that the sight hood has already been replaced.. Wonder how you work out what PFC's it uses??

Mike

*** Originally posted by claymore ***



Nakata, i knew i would get it wrong, i did think that the MGC's were the only one's that could be converted though. I supposse these nakata's are going to be expensive as well.

*** Originally posted by metradio ***


Cost me 500GBP complete with sling, 2 (x3) web mag pouches, 6 mags and the promise of a magfiller..

*** Originally posted by mark ***


Hi Mike,


Can you post pictures of the "detonator" in the firing chamber ? That would help us to determine the type of cartridge that it was converted to use as most of these used the "paper cap" cartridges that are not very relieable and these cartridges are hard to locate.

Also, there might be a chance that you might have an all zinc Marushin MP40 as I am not quite familar with the markings that you describe on the top of the receiver if so, then it uses the standard current model Marushin MP40 cartridges.

*** Originally posted by metradio ***


Don't know if these will help!!











Mike

*** Originally posted by mark ***


Thanks for the pictures Mike!

Sadly, I really can't tell what type of detonator is present in your firing chamber..I can say that it looks like it was recently added though and perhaps soldiered in place.

If it is original, it is possibly the paper cap type as opposed to the later styles of PFC cartridges. Also, I really haven't seen much in the way of the Nakata modelguns to make a determination on what exactly that detonator is for cartridge wise.

If the detonator is removable that would help immensely as then I could see it better check under the barrel nut and see if there is a set-screw under it that traps the detonator in place.

*** Originally posted by metradio ***


The pin is about 2mm in diameter, and about 5mm in length, with the tip off the pin being about 21mm inside the chamber. The pin is from new, and is a permanent fitting, with no means of removal or replacement..

Mike

*** Originally posted by mark ***


Hi Mike,

The pin that you describe is a stop pin. Not unfortunately, a detonator..As I had almost the same style of pin in my Kokusai P38 that I had..I think that the pin was meant to prevent the chambering of live amunition into the chamber.

I suppose that it needs either a new barrel or the pin to be machined out by a reputable machine shop in order to use a late model detonatr.

*** Originally posted by metradio ***


OK Mark thanks, any idea how/where I might be able to obtain a detonator or instruction to make one?? Also what dimensions whould the detonator chamber need to be machined out to to accept a detonator??

Mike

*** Originally posted by mark ***


Hi Mike,

Ok, what I usually do first, is determine the cartridge type that I want to use, this is usually determined by the cartridge availability issues more than any other factor.

The Marushin MP40/Uzi cartridges are good for may of these conversions as they are somewhat more available than the others like the MGC's or the Hudson cartridges.

I take the dimensions of the subject cartridge and note:

1. Overall length (26.5mm etc.)
2. Diameter of the cartridge body (9.5mm etc.)
3. Extraction grove dimentions
4. Nose aperture dimentions
5. "free" distance of the piston
6. piston type (flat etc.)

These all of course, factor into the detonator/chamber overall dimentions.

The existing factory chamber has to be checked for these important factors:

1. Can the original pin be removed?
2. Carbide anti-tampering/drilling blocks?
3. Is the barrel solid?
4. If the barrel is "open" (gasses out the muzzle?)
5. Is there a good way to afix the detonator in place?
6. Can the detonator be easily removed for cleaning?

As you can see, there is alot of factors determining the detonator/chamber relations.

Then, the replacement chamber/detonator designed with these factors:

Detonator:

1. Material: stainless or mild carbon steel?
2. Depth of reach
3. Afixment location (side or rear)
4. Holes for gasses?
5. Tip angles to match piston design (Marushin,MGC,Hudson etc.)

Chamber:

1. Material: stainless or mild carbon steel?
2. Depth of chamber
3. Diameter of chamber
4. Holes for gasses?
5. Extractor clearance?
6. Threaded holes for detonator afixment?
7. Hole with counter-sink for detonator afixment?
8. Chamber afixment location

So, I am not quite sure that I can suggest any really proper way to go about the conversion of your MP40...If I had your MP40's barrel, it would be different but, that's not really practical

I know that they convert the Nakatas to fire 9mm blanks in Britain, but I can't see that that is practical if you wish to "fire" the MP40 indoors as they would be extremely loud! so, I would at least think that there must be some machineshop in your neighbor hood that might be able to make a chamber or detonator for the Marushin or? modelgun cartridges that you choose for the conversion.

*** Originally posted by metradio ***


Hmm food for thought, thanks Mark.. Think my first move would be to get hold of a detonator and some matching cartridges, then work from there..

*** Originally posted by mark ***


Hi Mike,

Yes, you might try a Marushin MP40's chamber assy as they might be available from the modelgun collector or simular modelgun dealers in Britain.

That might a good start and then contact a machinist to do the mods to fit the chamber assy into the Nakata's barrel.

*** Originally posted by metradio ***


Had a play with the replica MP40 today and found out that the pin was just push fitted, I gave it a pull with some long nose pliers and out it came. So I took some measurements with the vernier - sorry about the drawing, not my strong point.. Replacing the pin was not so easy, I had to remove the refil from a ball point pen and use the end of the pen to refit the pin.
The only other features not shown are the feed ramp and the cut out for the extractor, there are no holes to allow gas to escape..
So it looks like a replacement can be turned (from stainless??) having a mounting pin of 2mm diameter and 4mm long..

*** Originally posted by mark ***


Hi Mike,

Nice drawing! I wish mine turned out that well!! Anyway, the pin looks like an anti-chambering pin and it looks like it could be machined easily for gas escape holes and a detonator..Well, maybe not easily but not that hard either...I would use a Marushin MP40 chamber (or simular) if space provided.

*** Originally posted by doc ***


Just to add my tuppence.

The barrel is definatetly Nakata but if the receiver is Nakata it should be marked "Nakata" on the right hand side of the receiver just above the plastic side pieces.
Interestingly Nakata MP40s usually have a nylon plastic front trunnion, there is another as yet unknown make that has this trunnion in zinc but this type does not usually have a barrel that extends inside it.

The pin that is inside is actually a detonator and was designed to be a very tight fit inside the cartridges this gun used.
They were solid brass, (very heavy) and had a small hole bored into the top. This hole was packed with gunpowder (I think) and sealed with either a blob of wax or tissue.
I only know this as my Nakata came with several of these cartridges and some were loaded and yet to be fired.
If you`ve managed to get your pin out it will proably be best to run a tap inside the hole and adapt a new Marushin detonator pin so it can be screwed in with long nose pliers.
This gun will only work with the marushin cartridges if it has the lightweight zinc bolt.
If it has the heavy one then you are best to fit one of the ABS bolt assemblies to make it work OK.

*** Originally posted by metradio ***


Forgot to mention the chamber is not removable, the barrel and chamber are a single item.
Apart from the 'MP40 72 0476' there are no other marking at all on the weapon. The trunnion is removable and of zinc, and the barrel extends all the way through it.
Not sure if it has a heavy or light weight bolt, how do you identify it

*** Originally posted by doc ***


You can now see the Metal Marushin and "unknown" plans here

http://g7hid.mysite.freeserve.com/Marushin_MP40.jpg

http://g7hid.mysite.freeserve.com/MP40_zinc_trunnion.jpg



Thanks to mike for hosting them, Mike yours seems a hybred of "unknown" make with a Nakata barrel, this is quite a good set up as you have a removable trunnion in zinc and the Nakata barrel is front venting.

Details on the two basic zinc bolts found in this type of MP40. They both look identical (same dimensions) and have the small tube protruding out the back a few inches . The older heavy zinc bolt is 464g the later lightweight bolt is 208 g, Its only this later bolt I have known to work ok with pfc carts, the heavy one will fire one or two and jam.
If you have a heavier type bolt I would recommend using one of the ABS bolt sets for using PFC carts.

*** Originally posted by mark ***


I often wonder just how many Japanese MP40 modelgun types where manufactured in the 1960's-1977 as there are quite a few that i have seen over the years that i have been looking. It would be a good idea to start a database on the various MP40 modelgun markings and details in order to catalog "who is who" as Nakata MP40's seem to have differ in markings and other details. The MGC MP40's vary considerably in details from the start of their production to their end in 1977. Other MP40 modelguns like the Marushin i know very little about as far as markings and details.

*** Originally posted by metradio ***


Might be an idea if someone who has seen a few different models of MP40, to compose a questionaire for the rest of us MP40 owners to fill in and post on the forum..

Doc wrote:

....Details on the two basic zinc bolts found in this type of MP40. They both look identical (same dimensions) and have the small tube protruding out the back a few inches . The older heavy zinc bolt is 464g the later lightweight bolt is 208 g....

Looks like I have the heavyweight bolt as it weighs in at 436g..
Had a look down the bolt tube and it seems like there is a lead insert inside the bolt..

*** Originally posted by mark ***


The different bolt weights must relate to their intended power loads that they where supposed to be exposed to. It's odd that the bolt weights change so much they might have changed due to production reasons only if anything. The MGC bolts changed continuesly during production and i am constantly studying them to see just what differences they have throught their years of production.

*** Originally posted by claymore ***


The markings on my Nakata are
MP40
EX68
No A2166

made in japan tokyo Nakata

That is all i can find on it.

Fired the Nakata for the 2nd time today and i have to say that i am impressed, the metal bolt gives it a good recoil effect and as the barrel is open (which is why i bought the nakata) you get a good smoke effect out of it. Also it sounds great pretty loud and metal hitting metal always sounds better. This is another MP40 i am falling in love with. I also have an ABS bolt for it which will fire faster i am told but to be honest i like the slower fire of the metal bolt and of course that recoil it gives.

I think the bolt i have must be the lighter version as it seems to work fine. I dont know why they made some bolts so heavy (felt recoil maybe) but i think one of the reasons my uzi never fires that well is because the bolt is so heavy.