[Austin W Hogan]

Speeds were measured with what is known as a ballistic pendulum. The shot was fired into a bullet trap on the bottom of a pendulum. The speed was deduced from the amount the pendulum rose.
I wish I had my old freshman physics textbook; it had a picture of a ballistic pendulum, and the math outline. It was a really good excercise to convert the potential energy of the pendulum back the the kinetic energy of the projectile, and then the speed of the projectile.

Best, Austin