Marushin m1 garand repairs

A few years ago I picked up a Marushin m1 garand. A previous owner had installed a connector for an air line. They didn't do a good job and the fitting leaked.

I picked up a surplus stock hoping that it would be usable. A lot of wood had to be removed from the inside. Using a carbide cutter in a Dremel I roughed out the inside close to the factory stock. Then I wiped on some black shoe polish onto the metal parts and tried fitting the stock. After a few hours of cutting I was able to get the stock to fit.

The stock is a close, but not exact match to the handguard. Since both are beat up I'm going to refinish them. With some staining I should be able to get them to match a little better. The real stock already makes it look much better.

Next I have to try to fix the receiver. Then make some clips.

I tapped the hole in the gas chamber for a 1/4" screw. I put on some Locktite 609 and installed the screw.

After a few hours of waiting for the Loctite to cure, I tried filling with propane. It was sputtering quite a bit while filling and didn't seem like it was filling right. I fired the rifle and it did fire, but didn't recoil enough to recock. I tried a few more times, but it didn't work any better.

I tried filling again. This time it refused to fill. After swapping out the fill valve it worked. The repair held full pressure.

I was able to get it to cycle a few times, but not reliably. Most of the time gas would vent out of the breech or out of the piston. I added more oil and it did get a little better.

It's probably going to need to be rebuilt with new seals. With the few times that it was able to cycle, it looks like it will be able to be restored into firing condition. Since the repair didn't leak I can continue with finishing it.

Thank you very much for this. It is very interesting.

I cut down the screw used for the gas chamber repair. After filing and sanding it smooth it was reblued. It's still noticeable, but gets covered up by the stock.

Previously I had been working on making clips. A surplus clip was trimmed to fit. A 3d printed section for the bbs slides in and locks into the ridge for the cartridge rims.

After some more lubricating and test firing it started cycling correctly. I tried firing a bb, but was just about out of propane. The action cycled and ejected the clip, but didn't fire the bb. I'm not sure if there just wasn't enough gas to fire or if there is more wrong.

Nice work, i was tempted with getting one a while back but it was in 8mm BB and as i already have 2 8mm models i would not buy another (marushin are finally changing their 8mm range to 6mm Hoorrah!)
I hope you get the valve sorted i have never had much succes in repairing leaky valves so i hope you have better luck than me.

I manually pressed the valve and gas through the port next to the nozzle. Thinking it might be my 8mm bb's I tried a 6mm in the nozzle. It still didn't fire.

Then it broke. I was that there was a steel replacement part made so I'm guessing it's a known weak spot. It's a complicated part so making a new one out of steel won't be easy.

I thought about modeling and 3d printing one. The other end also has to interact with the clip mechanism and is pretty thin. Even if the plastic could hold up to a few firing it probably wouldn't last long.

I degreased the parts and used Loctite 609 to permanently attach the broken section to the brass tube. That should make it stronger than factory. There also shouldn't be any reason why the brass tube would ever need to be removed.

I think I finally found the firing problem. A spring is supposed to hook under the left rod. That keeps it in the up position and allows it to push the valve for firing a bb. I'll have to wait for the repair to fully cure before I can test it again.

There is very little information on this rifle. There is almost nothing on the internals. I was able to find a disassembly video, but it wasn't in English. It also didn't show stripping the internals. That makes it hard to figure out how it is supposed to work or if parts are missing.

I've been having some problems with the printed clip. 3d prints aren't as smooth as an injection molded part so there is some binding. 8 8mm bbs take up quite a bit of space which doesn't leave much room to work with.

The spring I was using is too stiff. It would tend to bend instead of compress. I've picked up some less powerful springs to try. I do have a few ideas on how to improve the clip. It's probably going to take quite a bit of testing. There is also the chance that it never will be fully reliable.

I redesigned the clip to be a single stack. It pretty much completely eliminated the problems I was having with the double stack to single feed that I was using. It currently can only hold 4 bbs, but I might be able to squeeze another one in. The half capacity of only 4 bbs isn't ideal, but I'd rather have a reliable clip instead of a larger one that jams.

I also had previously started modeling a top handguard with integrated picatinny rail. It mostly worked, but a few changes are needed. It needed to be a few mms higher than a real one to clear the airsoft components.

There isn't room for it to attach with under barrel clamps like real versions. There are already screw holes at the rear for holding the barrel so I'll be using those instead. The front locks in like a standard handguard.

I tried again and this time the bb fired. Then the rifle broke again in the same spot. The front was still attached to the brass tube. The rear was only held in place with an o-ring. I Loctited the rear onto the tube. Hopefully it will stay together.