MGC M93R-AP Auto 9 disassembly : need some help

Hi,

First of all, pleased to join your community, and sorry about this first post as my MGC is not really a GBB but a GNB (gas non-blowback). Hopefully you'll pass this and help me in the maintenance of this old pistol.

My question is : I just got an old MGC M93R-AP Auto 9 gun. It's a replica of Robocop's one, and from what I read on the web, it's as old as the first movie. But it works (badly, but it works).

That's why I'm posting here : I'd like to disassemble it to "repair" (or at least understand the issue).

So, I removed the pin next to the trigger to remove the barrel extension (following a KSC dissambly video) but the extension won't go off. It looks like the extension is glued or something.

Does someone get this pistol and tried to disassemble it ?

Also, my problem is that the pistol shoot VERY softly... Even my old chinese 10$ Beretta M91 spring gun shoot x100 stronger. And when pressing gently the trigger (or pre-arming the gun), the armed pellet roll off the gun... Any idea ?

Thanks !

Welcome to the forum lpaso :-)

Unfortunately I didn't find MGC M93R NBB diagram in my archives or online... I only have KSC GBB and MGC PFC versions.

Soft shooting could mean that there are leaks in the mechanism - it probably needs lubrication or replacement of worn rubber parts. This should become easier to find after disassembly though

Not much help, I know.

smootik wrote:

Welcome to the forum lpaso :-)

Unfortunately I didn't find MGC M93R NBB diagram in my archives or online... I only have KSC GBB and MGC PFC versions.

Soft shooting could mean that there are leaks in the mechanism - it probably needs lubrication or replacement of worn rubber parts. This should become easier to find after disassembly though

Not much help, I know.

Thanks for your kind answer.
I made more tests, and the shot is more than soft, it's even inexistant sometimes ! I don't really know what to blam as the magazine (which contains also the gas) seems OK. From what I understand of my NBB gun, the hammer hits briefly a lever which hits the "gas trigger" (sorry, English not my language 😁) which releases shortly gas which ejects the pellet...

When the pellet is right before the hole from where the gas is released, it seems not to be well aligned...

Nice model, thank you for photos

What type of gas you use, green gas I suppose?
I found that some older constructions (like Maruzen Walther P99) are designed for HFC-134A. Pressure of green gas is too high, and hammer spring has too little force to fully open valve and let enough gas out to shoot pellet.
What you described seems similar to problem I remember with that Maruzen. You could get a can of weaker gas and check for that.

If that is the case, you would need to use HFC-134A. I think people tried to modify hammer spring to give it more force, but this is tricky and likely requires lot of testing.

smootik wrote:

Nice model, thank you for photos

What type of gas you use, green gas I suppose?
I found that some older constructions (like Maruzen Walther P99) are designed for HFC-134A. Pressure of green gas is too high, and hammer spring has too little force to fully open valve and let enough gas out to shoot pellet.
What you described seems similar to problem I remember with that Maruzen. You could get a can of weaker gas and check for that.

If that is the case, you would need to use HFC-134A. I think people tried to modify hammer spring to give it more force, but this is tricky and likely requires lot of testing.

When shoting, the gas is released correctly, loudly and with a big pulse, so I doubt the issue to be the hammer, but thank you very much for this advice. I'll try it to see what happens

I have doubts about the "nozzle" (the hole from where the gas isreleased and should push the pellet - is that the right name ?) as the pellet does not seem to align correctly nor is in direct and "hermetic" contact with it...

Could be nozzle alignement. Good luck