|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.