Yeah thats one of the guns, They decided not to make compatable with most other g36's, The new R-36's from jg are... simular.
It if was a DE Ump it would be a different storey.
I mean i can put a new spring and such in there cheap style (under 30 bucks) if your friend doesn't want a new gun.
But i cannot put my 120 day warrantee on it.