I have the chance to get my hands on one of these and a JG skorpion gearbox and I have an idea to fit the skorpion gearbox into the Marushin (wonder where i got that from 
).
For magazines I was thinking I could probably quite easily get RS magazines and fit some bog standard airsoft magazine mechs into them.
But my question is, will real steel magazines fit the magazine well, and work with the catch on the Marushin? Mind this is the blowback version that takes the bigger, incorrect banana magazines.
The answer is probably no because I'm sure if they did someone on here would have done it already, but I thought I would ask anyway.
Feel free to shoot me down!
AGM MP40 - AGM STG44 - CYMA Thompson M1A1 - WE P08 4 inch - Marushin M1 Carbine GBB - AGM Sten MkII
I believe I read somewhere that this gun will NOT take rs mags. I think it was on our American sister site.
pete.
"REMEMBER, LIFE IS NOT A REHEARSAL"
i am have just aquired a "dead parrot" New Spec Marushin M1 (the same as yours) and the mag holes on the back look like real mag parts. The main thing i remember reading though is that RS mags are smaller as the old school Marushin which i sold to Mirtrano i had to modify the pockets of the M1 to actually fit the gas mags ( a little slit down the centre of the pouch) Although i dont know in comparasion the size of the RS Mag. I am buying one to test out so il keep you posted.
On the Marushim 8mm non blow back M1, real steel mags are slightly too wide to fit in the mag well.
The airsoft mags do fit in M1 mag pouches, but it's tight... the reason for that is the bit that sticks out the top of the mag.
The Marushin M1 6mm airsoft mags that won't fit in M1 mag pouches at all.
