I have coin 50 piastri , 1956 , egypt .

I  have an coin 50 piastri , 1956 , egypt .  Mine has 22 g weight and 38,5 mm diameter ( argent ) , Numista has in catalog 28 g weight and 40 mm diameter . It is original or fake ? Please help me .

It's too off to be by accident. I think it's fake.

Thank you . Why to do with bad size ? Fake has the same size , i think . 

Size and weight errors are the easiest way to determine a coin's legitimacy, caused by inaccurate measures by amateur counterfeiters.