A ramrod is a metal device used with early firearms to push the projectile up against the propellant (mainly gunpowder). It is also commonly referred to as a "scouring stick". The ramrod was used with muzzle-loading weapons such as muskets and cannons, and was usually held in a notch underneath the barrel.
Bullets that did not fit snugly in the barrel were often secured in place by a wad of paper, but either way, ramming was necessary to place the bullet securely at the rear of the barrel. Ramming was also needed to tamp the powder so that it would explode properly instead of fizzle (this was a leading cause of misfires).
The ramrod could also be fitted with tools for various tasks such as cleaning the weapon, or retrieving a stuck bullet.
Early handguns were loaded a bit like muskets - powder was poured into each chamber of the cylinder, and a bullet was then squeezed in. Such handguns usually had a ramming mechanism built into the frame. The user pulled a lever underneath the barrel of the pistol, which pushed a rammer into the aligned chamber.