The difference in density of "tungsten" loads is that there are differing alloys with differing percentages of tungsten. The higher the density or purity the higher the cost. The highest commercially available density in a shell is 15 g/cc in Federal shells. It is not suitabe for older guns because of its hardness and the pressures in that shell. Winchester's version is about 12-13 g/cc and not suitable for older guns. Pure tungsten is about 19 g/cc. Gil