Swaging is forming metal using pressure. Casting is forming using heat. That's the simple defination. In swaging bullets a person uses one or more hollow dies and 2 punches, one at each end of the die cavity, to compress lead, lead alloy, or copper, into the shape of that cavity. Pressure needed varries, but is usually so high that a press made for swaging is needed (a reloading press is OK for pure lead bullets up to .45 cal or jacketed bullets up to .38cal). Recommend you go to the Corbin Co web site for more details. Set your search engine on "SWAGING" to find the site. Swaging, in my opinion, is about 2000 times more interesting than casting, and several orders of magnatude more productive. 8)