Biting the Bullet

At our workshop we routinely take delivery of high quality European timber, as shown in the picture below, which we then use to make our bespoke products. Last week was no different, except for a surprising discovery. 

This particular timber came from a sawmill in Italy, and when we were planing it up something got stuck in our machinery. We took a closer look, and found this. 

Yes, it was a bullet, that had got cut in half. We'd love to know how it ended up in the timber. Suggestions in the comments below, please!