Confederate Spherical 12-pounder

In some cases the Federal spherical case-shot projectiles contained the bursting charge in a metal cylinder.  The Confederates usually drilled into the case-shot to form the bursting charge cavity.  Due to the shortage of lead needed by the Confederates for small arms ammunition, iron case-shot balls were often substituted for lead, as can be seen in another example here.  This created a problem in that when the Confederates attempted to drill into the iron case-shot, the drill bit could not penetrate the hardened balls easily and would often bind, causing the matrix to break loose.