CARD Ballistic Pendulum.

[ashf9999]

Checked my eb*y history - August 2021 I paid £65.09 for a complete one with all the pendulums, paperwork and boxed. They crop up in traditional auctions as well every now and again.

Given the sheer number of reasonably accurate cheap chronos available now, the ballistic pendulum is little more than a curiosity. I remember school physics classes back in 1990 or so having a BSA Meteor (from memory) screwed down to a backboard with a similar ballistic pendulum attached to the same board about a couple of feet from the muzzle.