Buy Hunters Supply Hard Cast Bullets Lead Semi-Wadcutter Online. A great bullet for competitive shooting or small and medium-sized game, these high-quality cast bullets are composed of 6% antimony, 2% tin and 92% lead with a Brinell hardness of 15. They are rated to 1600 fps without gas checks. The bullet lube is designed for use with smokeless powder, but it will work with blackpowder firearms that have barrels less than 20″ long. The alloy is lab text certified before casting. This is not loaded ammunition.