The Prussian surgeon Dr. Bongard wrote in 1820:
Were French 8pounder guns still in use in the 1815 campaign, and in which batteries ?Amazing was the injury of a Landwehr man of the 2nd Westphalian regiment, whom a cannon ball of 8 pound weight was taken out of the thigh. I still possess this cannonball today, and all the staff of the hospital which was conducted by me was eye witness of this rare injury. This happened on 16th June at Géamblaux [Gembloux, north of Ligny], the wounded man died on 17th towards 7 o'clock in the morning.
A Prussian pound weighted 467 g, so this cannon ball would have had a weight of around 3,736 kg.