The Collaborative International Dictionary
Crossbar shot
Crossbar \Cross"bar`\ (-b[aum]r`), n.
A transverse bar or piece, as a bar across a door, or as the
iron bar or stock which passes through the shank of an anchor
to insure its turning fluke down.
--Russell.
Crossbar shot, a projectile which folds into a sphere for loading, but on leaving the gun expands to a cross with a quarter ball at the end of each arm; -- used in naval actions for cutting the enemy's rigging.