Source : Webster's Revised Unabridged Dictionary (1913)

Gunflint \Gun"flint`\, n.
   A sharpened flint for the lock of a gun, to ignite the
   charge. It was in common use before the introduction of
   percussion caps.

Source : WordNet®

gunflint
     n : the piece of flint that provides the igniting spark in a
         flintlock weapon