How to make the Marushin M500 take propane?

[CDN_Stalker]

I've been working on the Marushin M500 purchased from Fungus and he mentioned there is a mod to the relief valve he saw a while back to make it accept propane. Right now it only works on duster, is pretty weak, and when filled with propane it comes right out leaving about 2 shots worth of gas when it stops leaking.

Now, I can understand the use of a relief valve, but it is and odd find in airsoft from my experience. Is the mod merely plugging the relief valve so it won't leak or is it something else?

[Avenging Angel]

Theoretically all you would have to do is plug up the relief valve. But, it could also have adverse side effects.

The first thing that comes to mind is, how strong is the gas chamber? The engineers probably designed it with a certain pressure in mind (hence the relief valve) so, step one is making sure that the gas chamber won't explode with semi-heated propane.

Next thing I would worry about is the actual gas output vavle. Seeing as there would be more pressure on the valve, you could possibly damage the valve/valve spring and depending on how the output valve is designed, it could have a tendancy to leak under the higher pressures of propane. I'd pull out the valves from your gun and study them a bit more before you go ahead and make any modificaitons... just to be on the safe side.

[GMTII]

I dont think putting green gas/propain in any type of marushin gun is a good idea. on my marushin derringer I pretty much blew up the gas chambor becasue I tried filling it with propaine (luckey enough I found someone with a broken derringer so I just swaped parts) also I tried to seal the oversized o-ring on the derringer by covering teflon tape over it but it still didnt work with propain. And when I tried putting propain in my marushin kar98 it just all leaked out. same thing aslo happeded with my marushin browning 1910.

I really wouldent advise using propain/green gas.

Erik

[CDN_Stalker]

Hmmm, ok. It came with replacement valves, so I am familiar with them. Read on a forum during my unsucessful searches that a guy plugged up his over pressure valve and has run green for about 1000 shots without problems.

I wish the thing performed well on duster! Then again Fungus told me at one point it was cool out and he ran propane through it not problem (stayed in) and used duster when it was hot out. I suppose that if I plug one of the overpressure valves and treat it like my KJW M700 (over 20C use duster, under 20C use propane) I might be ok. At this point I've only been using it in my basement and it's not overly warm down there.

[lamlok]

The M500 is the most robust shot gun on the market. It can accept green gas with no problem (I have 2 6mm wood cruiser)
You can fix the gas leaking problem by the following:
1) replace all rubber O ring at the gas chamber
2) replace a stronger hammer spring
3) take out the gas leaking valve, replace it with a big screw (remember to use lots of screw lock to make sure it is air tight.

after all this, you will have the best weapon available (can use up to red gas)

[CDN_Stalker]

Hmmm, there is something I was hoping for! Thanks Lamlok, I'll look into this.