This is absolutely hilarious. A broken hand as the only injury is lucky though. I haven't laughed as hard as I just did in a LONG time. Thanks for the laughs.
At the risk of ending up with egg on my face, I'm going to take a "shot in the dark" and go with: a blacksmith's scale that was used to weigh hollow cannonball grenade projectiles. This tiny, rare ammunition was used in the Revolutionary War. They had to be between 16 and 40 ounces to be used (?)