Yes, just one of the many frustrating and foggy areas of naval collecting. I like the bronze gun for the 'Tops'. It would have done well against boarders.
I don't necessarily question Mr. Gilkerson, but I feel that his study concentrated particularly on one country's type of grenado from a specific time period (Great Britiain, ca. 1600-1750-ish). As we've seen on this forum, there were all manner of exploding shells around made in different materials (clay, stone, etc). Perhaps in the future, someone will do a more definitive and specific volume on said lobbed bombards.
Here's mine from an old link. As I said, it's smaller than the examples Gilkerson mentions, bigger than golf ball but smaller than a tennis ball, approx 2 1/4" tall with a hole the size of a garden pea (at this small size, I imagine just enough room for a wick with no inner core, as some do-
http://www.vikingsword.com/vb/showth...t=hand+grenade