Practically all shot has always been made by pouring molten lead through a plate with holes in it and letting it fall for a distance, which forms the droplets into little spheres. They then fall(fell) into water, which cooled them and caused a very slight hardening.
The first was pure soft lead, but eventually had slight amounts of antimony added to it to harden it. The antimony hardened shot then became known as chilled shot and the pure lead shot became known as drop shot.
The word "chilled" really does not imply that it was chilled any more than drop shot. Just their way, at the time, of differentiating between the two.
This info from George C. Nonte's Firearms Encyclopedia, copyrighted 1973.
SRH
