WE 5.1 Hi capa part replacement
 

There's this little square thing that's suppose to go in the metal hammer looking part that broke off. I don't know the name of the parts but if I can't find that small piece, is it possible to get the whole part replaced? If so, what is the part called?

Are you talking about the little black piece of plastic that retains the inner barrel to the outer barrel?
I bought some from tiger111hk a long time ago maybe they still have that part in stock.

Yes, that's the small square plastic piece I'm talking about that goes in that square hole.

I believe this is the part:

http://airsoft.tiger111hk.com/p18105...duct_info.html

Thanks