MGC MP40 Detonator Pin problems...

Post by Reemo

Hi Guys

And specifically Mark.....I have received the detonators from Francky, but things havent worked out well.


I ordered the Marushin detonator for the MP40.....it doesnt fit. I mean, at ALL.

My MP40 has the stock paper cap detonator in it.....and it fits in beautifully.

The Marushin detonator, first, does NOT sink into the hole in the trunion....the hole would have to be enlarged to accept the new detonator (at least 2mm).....is this normal? I didnt want to drill anything.

NEXT, when the barrel is reinstalled and the barrel nut tightened all the way, there is NOTHING pressing against the back of detonator to keep it in place.....its got at least a half an inch of air behind it.......was there some sort of spacer that is supposed to be in there? Maybe got lost?

You guys are the experts, please let me know.......Im ready to toss all these toys out the window.

(PS....the detonator I bought for the Sterling doesnt work either!!! )
_________________
"This is your life......and its ending one minute at a time."

Post by Claymore

Mark will probably be the best to help on this, but i do believe Francky can get the proper type detonator for the mgc mp40, he got one for my sterling and what about the sterling you have, have you tried the detonator from that they should be the same i think

Post by Reemo

Hi Claymore
Thank you sincerely for your help here.

The Sterling will be the easiest to get going of the 2 guns....least amount of mods.

You can help me with the Sterling......did yours originally have the little metal plug in place of the Detonator? Did you have to drill out the hole slightly so it would slip in?

I ordered 2 detonators for the Sterling.......the CP type and the PFC Marushin type.....so I would have options.

Which did you go with? I think you said you prefer the 220 cartidges (CP type) and I would agree......the Marushin cartridges just dont move that heavy bolt and they are not loud at all. (Often make NO noise at all)

Let me know.......

Neither the CP or PFC detonator fits properly in the old MP40......the dimensions are waaay off in all respects.
_________________
"This is your life......and its ending one minute at a time."

Post by Mark

Reemo,

It appears that your MGC MP40 is just like my very early example in so-much that it has the recessed trunion which I believe is meant just for the paper cap detonators use. Is your trunion chromed? And, does it have any extra holes drilled into its exterior? This earlier deeply recessed trunion caused me all sorts of trouble.

However, I simply made a really thick steel washer to take up the extra room that the recess had in it, that prevented the detonator from being held in the right place.

As for the hole for the chamber being too small, that is the norm on these early examples.

I would advise that you don't drill the trunion I would however reduce the size of the detonator's forward section. Now, I am not sure (nor do I remember what I did on my MP as I later changed the trunion to a later example.) if the early trunion's chamber isn't deep enough or what. So, I would say that you need at least two thick steel washers, one in front and one in the rear of your new detonator. If the washer isn't placed in front of the detonator then the chamber will not be deep enough to work for the later cartridges.

I think that you have to balance the detonator length front/rear to make it right...

Again, I have already gone through this ordeal myself and it is frustrating as I too, would like these models to be "plug and play" but sadly they aren't that way.

As for the Sterling, they should all have the "plug" if they haven't been removed by someone else.. I didn't have any problems with its (with the exception of having to make a new bolt for it ) detonator as I machined my own by copying my MP40's detonator. I think that you will need to either drill the chamber or machine the replacement detonator to fit.

It's too bad that we have to struggle to make these toys work but they can be worth it in the long run..
_________________
Wanted to buy: MGC Sten MK3....trades?(still)

MGC MP40 Marushin MP40 Nakata MP40 TRC MP40

Modelgun manufacturers, past and present:CMC,CAW,Hudson,HWS,LS,MGC(R.I.P. 1960's~2007) Marushin,Marui,Kokusai,Shoei,Tanaka and Western Arms

Last edited by mark on Fri Jul 07, 2006 7:49 pm; edited 1 time in total

Post by Claymore

Hi Reemo, yeah i had the metal plug in there, the barrel i have is blocked and to be honest as the bolt was also cut i have never got around to fit the new det pin or even try it seemed pointless without a bolt that worked.

By the way my bolt chamber and barrel have gone off to mgc so they can have a look and price up replacements, fingers crossed the price is not sky high. Might be worth contacting them as they have had a lot of mgc mp40's pass through their hands and may be able to help with advise and/or parts.

Post by reemo

Hi Guys!
Thank you BOTH very very much.

Mark - you've been there! You know exactly what I am going through. Yes, it is a chrome plated early trunion.

Jeesh....the marushin detonator will require all KINDS of rethinking.....

It (the pin) is indeed protruding too far into the chamber......it will have to be spaced back. I may have better luck with the shorter CP detonator.

In the meantime, I have DESTROYED 5 marushin 9mm cartridges.......and Im still nowhere close to getting things "worked out".

Im going to give it a shot tonight and this weekend, but I think I may just give up.

BTW......Im not sure how I could reduce the front of the detonator - it would be easier to drill the trunion to the correct depth. I have a drill press and the correct (X) bit........but I dont have any way to mill the brass down......any suggestions?
_________________
"This is your life......and its ending one minute at a time."

Post by Mark

Quote :

Im not sure how I could reduce the front of the detonator - it would be easier to drill the trunion to the correct depth. I have a drill press and the correct (X) bit........but I dont have any way to mill the brass down......any suggestions?

Ok, since you have a drill press..Do you have any metal files? If so, place the detonator in the drill presses chuck and use the file to reduce the detonator while it is spinnig.
The only way to fix the MP40 is to either correctly space the detonator or replace the trunion...The early MGC MP40's are difficult at best to convert properly due to their odd trunion.

Post by reemo

Mark, thank you sincerely for the lengthy reply - you have indeed experienced what I have here. How lucky you were to have another trunion to replace it!! I wish I had the luxury.

Well, there is some good news.......I fitted a detonator to the Sterling - it was the easier of the 2 problem guns so I took a shot and had success.

Thanks for talking me OUT OF drilling the trunion......I did as you said and put the detonator in the press and put the file to it......great advice (You clever dog!). A poor mans mill!

Now the bad news; these Marushin Cartridges.

HOW do people get these "O-ring-less" cartridges to work?!!? They dont make ANY noise......a slight "poof", a wisp of smoke, and a slightly warm cartridge......they dont blow the Sterlings bolt back.

So, I switched to the strong stuff.....Kane "Pink Box" caps......well, they certainly blew the bolt back!! MY LORD! They are still the loudest strongest caps there are......approaching 8mm blanks in loudness (when installed in these Marushin cartridges - TIGHT fit).

However review below........they literally blew the Hell out of the shells.........




MAN! They were loud......ears ringing loud.....they dont get that loud in the 45ACP shells, but the tight fit in the Marushin 9mm makes for some serious volume.

So I have given up on the Marushin Cartridges.......so give me some help again.......is it the MGC (CP) P220 cartridges that many of the forum members use in place of Marushin 9mm?

I have the CP detonator so that is the direction I am going.

I look forward to your confirmation on the cartridges.....next stop, MP40.
_________________
"This is your life......and its ending one minute at a time."

Post by Mark

Quote :

HOW do people get these "O-ring-less" cartridges to work?!!? They dont make ANY noise......a slight "poof", a wisp of smoke, and a slightly warm cartridge......they dont blow the Sterlings bolt back.

Well, I think that the main trick to using the Marushin MP40/Uzi cartridges is to use grease in them and make sure that the base is tightly screwed on. The use of grease on the insides of the cartridge allows the piston as well as the cap to slide easier as it eliminates friction. Admittedly, the sound that is produced by the Marushin PFC system cartridges is very weak but, in some instances I like the low noise level as I can shoot them in the back yard.

Quote :

So, I switched to the strong stuff.....Kane "Pink Box" caps......well, they certainly blew the bolt back!! MY LORD! They are still the loudest strongest caps there are......approaching 8mm blanks in loudness (when installed in these Marushin cartridges - TIGHT fit).

Kane caps that are packaged in a PINK box??? Do you have a picture of these caps? Obliously, they are far too powerful for the marushin cartridge design WAY too much gas pressure for their design to take!

Quote :

So I have given up on the Marushin Cartridges.......so give me some help again.......is it the MGC (CP) P220 cartridges that many of the forum members use in place of Marushin 9mm?

Yes, they are the cartridges that everyone is running and that is what the CP detonator is designed for. For the most part, I like the 220 SIG cartridges as they work far better than the Marushin cartridges. However, most of my like for the Marushin MP40/Uzi cartridges comes from the fact that they where simply the easiest to find/buy and the SIG 220 hadn't been produced since 1994 or so. That caused the cartridge supply to be fairly low in Japan and they seemed to be rare.
I don't know if MGC has changed the SIG 220 cartridges "pistons" to the O-ring type as the older cartridges used the CP (Cap Piston) type pistons. These pistons used either an old fired cap with a small hole in their center or the MGC supplied "starter" cap bodies that where produced with out powder and where just meant to give a starting set of "fired" caps to use.

Post by Claymore

Mark the new sig p220 round is the rubber seal type and work great and i mean really really well and last a hell of a lot longer than the marushin rounds, they have a new sig 220 model so rounds dont seem to be a problem, thank god.

Post by reemo

claymore wrote:

Mark the new sig p220 round is the rubber seal type and work great and i mean really really well and last a hell of a lot longer than the marushin rounds, they have a new sig 220 model so rounds dont seem to be a problem, thank god.

Okay - well that settles it......Im going to try these instead.....I cant get the Marushin cartridges to work with any consistency......I used the same SS high temp grease that you use Mark.....a light film.....any more inside usually fouls the cap.
Next stop......MP40 Hell!

Post by reemo

Woo-hoo!

A friend of mine has helped me to get the MP40 firing!

What a LONG road, but it is now firing. I have ordered the CP (MGC Sig) cartridges, but I coudnt wait until next week.......I rigged the Marushin cartridges/detonator to fire today.

Mark, I spaced the detonator as far back as I could.......turns out, I needed all that space ("air") behind the detonator to get the pin further back in the chamber.......Im not sure if that space behind there was by "accident" or by "design" - only MGC knows for sure.

With 2 THICK custom machined washers in front of the detonator, the barrel holds the detonator tightly in place, with the barrel nut cranked all the way........ And the pin is right where it needs to be so that cartridges work properly, and the extractor can grab the shell.

Now,......I have to say....there is NO BETTER feeding and extracting model gun than the vintage MGC's,.......NONE. This thing fires flawlessly.......20 rounds, no jams......mag after mag. Just like a vintage MGC Thompson. (Still giggling!)

I must be honest, I am NOT happy with the "quiet-ness" of the Marushin shells, but they did work well in the gun.......I will still try the MGC cartridges and see what happens with them......I will have to "juggle" spacers and washers again to get the pin where it should........but it will be worth it, indeed!

(MAN, that heavy bolt clacking away was soooooo satisfying!! )
_________________
"This is your life......and its ending one minute at a time."

Post by reemo

Reemo wrote:

Woo-hoo!
A friend of mine has helped me to get the MP40 firing!
What a LONG road, but it is now firing. I have ordered the CP (MGC Sig) cartridges, but I coudnt wait until next week.......I rigged the Marushin cartridges/detonator to fire today.
Mark, I spaced the detonator as far back as I could.......turns out, I needed all that space ("air") behind the detonator to get the pin further back in the chamber.......Im not sure if that space behind there was by "accident" or by "design" - only MGC knows for sure.
With 2 THICK custom machined washers in front of the detonator, the barrel holds the detonator tightly in place, with the barrel nut cranked all the way........ And the pin is right where it needs to be so that cartridges work properly, and the extractor can grab the shell.
Now,......I have to say....there is NO BETTER feeding and extracting model gun than the vintage MGC's,.......NONE. This thing fires flawlessly.......20 rounds, no jams......mag after mag. Just like a vintage MGC Thompson. (Still giggling!)
I must be honest, I am NOT happy with the "quiet-ness" of the Marushin shells, but they did work well in the gun.......I will still try the MGC cartridges and see what happens with them......I will have to "juggle" spacers and washers again to get the pin where it should........but it will be worth it, indeed!
(MAN, that heavy bolt clacking away was soooooo satisfying!! )

Congratulations Reemo!
The MGC MP40 does shoot rather well when it is dialed in doesn't it? When I made mine fire for the first time I was astounded that it worked so flawlessly! I fired,cleaned and loaded alot of rounds that day let me tell ya..
Yes, the Marushin cartridges are certainally quiet compared to the other types of modelgun cartridges. But they are great for their price and the fact that they are still the least expensive (as well as the most common) modelgun cartridges that are around today. The fact that they are so easy to get makes them my personal favorite.
Besides, the Marushin PFC Uzi/MP40 cartridges have been in production for a long time and they will be around when I need more.
The Sig 220 cartridges are great I am sure but, unless more of them are sold they will remain expensive and hard to get. Plus, I have only five of the 220 cartridges so, I really haven't experienced them myself.
Modelgun cartridges are like gold to me as they are of course, the heart of the modelgun and replacement cartridges are always on my mind when I shoot any of my modelguns. I like to have several brand new backup cartridges to replace any "woops" cartridges. (you know those cartridges that are crushed by the bolt etc.)
So, I tend to look at modelgun cartridges differently than others.