Ok, I already know the deminsion difference between a bofors and a 40mm grenade round, and your point is what? Did he say how big the round was?
No specifics yet on round involved, I just posting pics in response to your reference to Bofors 40mm remark, hope it helps give some scale to possible round.. I had a couple teachers that had spent 20 and 40mm rounds as doorstops and shelf display.