In early days, due partly to the roughly made balls, wads were very
important as a means of confining the powder and increasing its
efficiency. Wads could be made of almost any suitable material at
hand, but perhaps straw or hay ones were most common. The hay was
first twisted into a 1-inch rope, then a length of the rope was folded
together several times and finally rolled up into a short cylinder, a
little larger than the bore. After the handier sabots came into use,
however, wads were needed only to keep the ball from rolling out when
the muzzle was down, or for hot shot firing.
Gunners early began to consolidate ammunition for easier and quicker
loading. For instance, after the powder charge was placed in a bag,
the next logical step was to attach the wad and the cannonball to it,
so that loading could be made in one simple operation--pushing the
single round into the bore (fig. 48). Toward that end, the sabot or
"shoe" (fig. 41) took the place of the wad. The sabot was a wooden
disk about the same diameter as the shot. It was secured to the ball
with a pair of metal straps to make "semi-fixed" ammunition; then, if
the neck of the powder bag were tied around the sabot, the result was
one cartridge, containing powder, sabot, and ball, called "fixed"
ammunition. Fixed ammunition was usual for the lighter field pieces by
the end of the 1700's, while the bigger guns used "semi-fixed."
In transportation, cartridges were protected by cylinders and caps of
strong paper. Sabots were sometimes made of paper, too, or of
compressed wood chips, to eliminate the danger of a heavy, unbroken
sabot falling amongst friendly troops. A big mortar sabot was a lethal
projectile in itself!