of a jacket to produce a bullet the monolithic metal insert permits expansion while the powder metal core provides mass initial prototypes were made following procedures employed in the fabrication of lead hollow point bullets commercially available lead hp bullets were analyzed and designs for non lead versions were developed it was determined that a bullet with an 80 grain tungsten tin w u2014 sn composite core a 40 grain monolithic tin insert and a 20 grain copper alloy jacket could be used to produce a 140 grain 38 caliber hollow point bullet that matched the dimensions and weight of the lead design the invention required a mixture of 75 wt tungsten and 25 wt tin which produces a material with a density of u02dc 14 g cm 3 an 80 grain composite core 0 309 u2033 diameter was fabricated by compressing the w u2014 sn mixture at room temperature and 50 000 psig pressure the core was seated in a 0 500 u2033 long 0 357 u2033 diameter copper alloy cup or jacket using a hand press the appropriate die and a punch with a flat face the inside diameter of the jacket had been u201c scored u201d along six equally spaced longitudinal lines to promote failure during expansion a 40 grain tin insert fabricated from extruded material was then seated on top of the pm core using a punch that produced a hollow tapered preferred conical cavity in the tin another die and punch were used to form a nose on the bullet this produced.