*** 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..