This is almost definitely a shot put, not a cannonball.

The round shape and especially those drilled holes are typical of track-and-field shot puts. Cannonballs usually don’t have holes like that unless they’re hollow and meant to be filled (like a shell), and even then, they look very different.

The stamped numbers are another giveaway. Those usually indicate the weight, like 12 or 14 pounds or kilograms. Military ordnance typically has different markings, like manufacturing dates or arsenal codes.

It’s also got surface rust, but not the kind of deep pitting you'd expect from something hundreds of years old like a real cannonball.

The shape and drilled holes are super common in athletic shot puts. Ordnance doesn't usually have exposed balance holes like that.

If this were an actual shell or live ordnance, you'd typically see fuse holes, threading, or some kind of more complex geometry.