[Ricklin]

The printing on the side of the hull is my clue here, and the gauge.

Are you sure they were 00 buck? What do I think they actually are?

There is an 8 gauge gun used in foundries to blast the "clinkers" I think the term is from inside the crucible or furnace for making steel.

8 gauge specialized gun made for foundries, pretty sure they are slugs, however I have only heard and read about them.