​Large iron ball, 23kg, 18cm diameter, magnetic, flat spot to one side, pronounced cast seam with sprue mark on the seam

Hi all,

Purports to have been found in Cornwall a number of years ago.

23kg-ish, 18-ish cm diameter, casting mark and sprue mark on the casting mark line.

Flattened spot to one side, with crushing consistent with some sort of impact.

Looks like a cannonball to me, but closer to 50lb than the 42lb that standardised cannonballs seem to have maxed out at.

What do I have here?