Capt. Jas. is absolutely correct.
Page 130-2, direct quote:
"Before 1665 shot (As distinguished from swan and buckshot, which have always been cast in gang molds) was made by the laborious process of cutting sheet lead into cubes and then tumbling them in a barrel to more or less round off the corners."
Though the following chronological order for making what we today would call "bird shot" is taken from the book, it is not exactly as written. (Sorry, It is too hard to hold and read and type from a soft cover book to get that wording exact.) BTW, they also used the Drop Shot Technique to make Musket Balls.
Before 1665 - Tumbled Shot cut from sheet lead and then tumbled for rounded edges, though not completely round
1665 to 1769 - Rupert Shot, Ovoid/Heart shaped shot, often if not usually with a dimple in it
From 1769 - Drop Shot (from Drop Towers) which was very uniformly round
Calling "Tailed" shot or "tear drop shape" shot by the term "Swan Shot" is a MODERN Misinterpretation of the original 18th century documents. I first remember seeing it so incorrectly called "Swan Shot" in the 1970's, but don't remember if it was in Muzzle Blasts, Sketch Book '76 or some other publication. I do remember drawings being exaggerated to look more like a Swan than the more common Tear Drop or Tailed shape, though.
Gus