A bullet for use in injecting substances into molten metal comprising an elongated body and a nose affixed to one end of said body, said body containing a substance which will react in molten metal to form a reaction product, said reaction product being emmisible with said molten metal, said substance having an exterior which is continuously in an exposed condition to said molten metal so as to react with said molten metal throughout the period in which said body of said bullet is in remains contacted by but unreacted with said molten metal, and said nose being composed of a metal for alloying with said molten metal.