What Upper Receiver is compatible with a metal specna arms SA-A03?

[O-53]

Hello all,

I have a specna arms SA-A03 MK18 which is part of the specna arms ONE series (separate and not as popular as the core and edge series) which I'd like to find an upper receiver for. 

I've looked around and found the original metal receiver online (around £70) however I was wondering if anyone knows or have tried any other upper receivers that are compatible and could substitute it.

Thanks

 

[Lozart]

I also have an old SA-A03, they were OEM'd by E&C so their receivers should fit ok. https://www.firesupport.uk/replacement-parts.html?manufacturer=943&product_types=755

 

[ak2m4]

I'm sure I have a spare E&C upper brand new around, yours for £20 if I can find it and if you want it?

 

[O-53]

I also have an old SA-A03, they were OEM'd by E&C so their receivers should fit ok. https://www.firesupport.uk/replacement-parts.html?manufacturer=943&product_types=755

Had a look they seem to look the same? thanks man