Marushin MP40 Receiver Tube & ROF Mods

Post by evil_kot (see also https://mp40modelguns.forumotion.net/modelgun-modifications-f7/marushin-mp40-rate-of-fire-stuff-contd-t487.htm#3284)

Guys, does anyone know if real metal MP40 receiver [correction - I meant a receiver tube] is compatible with the MP40 Marushin kit? It would be cool to replace that pathetic plastic thing.

Thanks!

Post by John

Sorry that I could not help as rifle is not my cup of tea.

But I heard that the receiver is one of the critical parts of real firearm. And it is likely that the Authority may regard a modelgun modified with this real receiver as a real firearm. If this is true or likely to be true, I think it is not worth to modify the modelgun with real receiver.

In HK, the only part that is surely legal to modify / replace on a modelgun is the grip or stock.

Post by evil_kot

Well, I’m not a lawyer, but I do not think they would be able to prove that a gun with the barrel plugged by a piece of metal, and with the firing pin pointing towards the user is a “real” gun.

What I’m talking about is that it might be fun to replace all plastic parts that possible with the metal ones. I’ve seen in the internet that a lot of original or metal replica parts are on sale, and prices are pretty reasonable. If you buy a part every 1-2 month, in a year you’ll have a unique piece of fun/hobby/collection.

Post by John

Hi,

Well, I would say this modelgun hobby is a very sensitive hobby as it is already too close to the real ones, even with their original plastic parts.

Anything that is uncertain or in grey area should have some risks to certain extent. The law to define firearm is of course different place by place and could be changed easily - like that in Taiwan.

In fact, gun control in HK is very tight. Just possessing the obvious real firearm parts (except the grip / stock) without licence will already cause the holder enough trouble if caught by police. It is surely not a grey area here but an obvious & serious offence.

It is better to play safe rather than go deep into the grey area or risk the potential trouble.

Good luck.

Post by Mark

Hi evil_kot,

The receiver tube on an MP40 is actually the machinegun! Not all of the parts! If you had a actual registered MP40 receiver then I suppose you could assemble the Marushin parts on it but, it would still be a federally controlled machinegun! Plastic dummy parts or not!

The ATF would consider you to be assembling an un-registered post 86 machinegun, if you where to make a replacement steel receiver tube for it as the Marushin is very close to the actual MP40's dimentions..Not a good idea!

If you want a legal all metal MP40 modelgun, buy a MGC...

Post by evil_kot



OK, we’ll see.

One more question, guys: I’ve heard somewhere (maybe even at Mark’s site) that the Marushin model has too high fire rate, like 700-800/sec, while the real thing has about 500/sec. And with a little adjustment/tuning you can lower the fire rate close to the real. What is that adjustment would be?

Thank you!

Post by Claymore

There are loads of metal bits that you can get for airsoft guns (very expensive though) and they are made specifically for them. I have never seen purpose made metal bits for modelguns.

I think you would find that any metal parts you could find would be the wrong dimensions for model guns as i do believe the model gun manufactures deliberatly make the guns slightly smaller in dimension so that real parts cannot fit.

As well as that i think you would have to be pretty good on model making and adapting your own parts to get the model to work with metal replacement parts, its hard enough to get them working with the original bits at times.

As far as reducing the rate of fire i think that would come down to replacing the spring but doing that could cause jamming and misfeeds etc. To be honest i have no idea what the rate of fire for my MP40 is but i would not want to reduce it as it seems about right and you can control it well with 2-3 round burst if you so wish.

I would say if it aint broke dont fix it.

Post by Mark

evil_kot, The Marushin does have a rather fast rate of fire as the rate is around 800! rounds a minute instead of 5-550 rpm of the original MP.

The rate of fire should be closer to my MGC but even my MGC's ROF is too high around 560 or so. The slow ROF gives the MP40 it's distinct sound and adds to the length of time that you can enjoy firing either the real MP or the Marushin.

What you can do is add weight to the bolt assembly as the Marushin bolt is too light as it is mostly plastic. The weight can be added to the inside of the hollow bolt body (lead wheel weights)

claymore,

I have noticed that some Japanese airsoft manufacturer is giong to release a metal airsoft version of the MP40! That should be cool!

As for the dimentions on the Marushin MP40, they are almost 1:1 the Marushin is the best MP40 replica out in the market as many of the important features work (the bolt handle safety works,the muzzle nut has threads and a wire friction spring etc.)

Post by evil_kot

Thank you Mark! I'll experiment with weights whem I got my caps. I'll let you know if it works.

Post by Claymore

i did not know that the mp40 was that close to the real thing in spec, Still dont fancy messing around with it though as with my luck a very good working gun will turn into a combined metal/plastic mess.

Air soft Mp40, now that does sound interesting maybe some bits would interchange although i am not sure what you would or could want to change. The MGC M4A1 has its airsoft brothers and there are loads of bits and bobs you can add on.