W9 ... I do not know the actual metallurgy of the piece but ..... I am sure this is not pot metal .. it is too heavy and the metal seems way harder.Also, this is a pot metal gun as far as I know
Similar thing here Peashooter ... but I was lucky. What had happened was the pin end had not been peened enough and ''button'' popped off.The mag release button came apart. I tried to repair it by simply reassembling it, but the pin was broken