from the GNU version of the Collaborative International Dictionary of English
- a shot made to ascertain whether the sights of a firearm are properly adjusted; a trial shot.
from The Century Dictionary and Cyclopedia
- n. A shot made for ascertaining the qualities of a firearm, and discovering whether the projectile will strike the spot aimed at, or another point a little above or to one side of it, as is often the case.
Sorry, no etymologies found.