Many thanks
I got a chance to have a look in an old museum collection today and found another 6 pounder and a 24 pounder, each ball with a similar stud (1st attached image of the museum’s 6 pounder, 2nd the 24 Pounder). Sadly, no further info available. What are the odds of the museum also having such similar balls?
Fernando, thank you for the image. The studs must be part of the manufacture process. It vaguely looks like the mould seam runs around the balls’ circumference, 90 from the stud but it’s hard to tell. The stud is very solid and sprue-like, roughly 1/2" wide. M ELEY, all of those are ideas seem quite plausible the 3 1/2 ”-ish ball with the stud weighs 2707g, I also have a known 6-Pdr wreck recovered ball which weighs roughly 2300g so maybe the stud one is filled with bronze? There is only 1 stud, same with the examples in the museum.
Also attached is an image of some bar shots acquired at a similar time.