The Americans as we know like to use Legacy Units. Hogsheads, bushels, pecks, roods, furlongs, yards and a whole panoply of unrelated units of measurement called after things like the distance between one English king’s nose and his outstretched arm.
Here we find an artillery piece whose weight is quoted in Legacy Units. Fifty of a larger unit, one of a subdivision and twenty-three of a further subdivision. The weight corresponds to 2,563 kg.
Now, what are the three different units?