Precision forged cartridge case

A trimming apparatus for producing a uniform sheared edge on a tubular work piece having an axis in a multi-station cold forming machine comprising

• a collar with a circular bore defining an axis and adapted to slip over the work piece, the circular bore having a sharp peripheral edge lying in a plane,
• a tool with an end sized to fit in the work piece, the tool end having a sharp edge, and
• a mechanism having relatively movable elements that produce radial motion of the tool relative to the axis of the circular bore and orbital motion of the tool about the axis of the circular bore, the mechanism being adapted to provide sole axial support of the tool from only a side of the plane of the sharp peripheral edge remote from the collar,
• the tool and collar edges during such radial motion and orbital motion being arranged to shear the tubular work piece to sever a ring therefrom and produce said uniform edge.