Here is a seldom seen mold. It is brass or bronze, 38 caliber, and faintly marked "Allen & Thurber". Similar molds have been observed which were not marked by the maker. The mold casts a smooth conical ball, presumably for use in one of the little Allen & Thurber pistols made before the Civil War. Notice the very complicated sprue cutter. The sprue cutter is actually composed of two separate iron plates. The purpose of the "extra" plate is to allow the base of the bullet to be convex. In order for that to work, the cutting plates have to be hinged to lift up above the little convexity that remains. The bottom panel in the composite image shows the contour of the thin cutter on the side toward body of the ball; it has a rounded profile which would be left as the base of the conical ball.