Okay, actually it's a collector's piece; the tube has been modified to make it not possible to drop the shells down it, and the firing pin in the base is gone too.
It's an 81mm mortar, model now forgotten. Each of the three pieces (tube, front support, baseplate) weighs about 45 lbs. The ammunition is about 10 pounds a round. So you don't carry this with you unless you think you'll really need it.
Actually "mortar" was why I was over there -- the chimney needed some remortaring, and Greg needed help setting up and taking down the scaffolding he used to reach it.
