Source : Webster's Revised Unabridged Dictionary (1913)

Ramrod \Ram"rod`\, n.
   The rod used in ramming home the charge in a muzzle-loading
   firearm.

Source : WordNet®

ramrod
     n 1: a rod used to ram the charge into a muzzle-loading firearm
     2: a harshly demanding overseer
     3: a rod used to clean the barrel of a firearm