Part of my analysis in that 2013 discussion was, it seems there is no surviving historical document which tells what the caliber of the Sumner Oscillating Cannon was. So how can anybody claim that these Milledgeville bolts were made for use in it?
I'll add that it seems unlikely that the Georgia Railroad's machining-shop would have the necessary equipment laying around (and the necessary expertise) to cut rifling-grooves inside the barrel of a cannon.
Some of the information floating around (such as the Georgia Railroad machining-shop stuff) is said to be taken from a 20-something-years old magazine article written by Beverly DuBose. Does anybody here have access to that article, and if so, could it be scanned and posted here, so we could see exactly what it says, and doesn't say? Theoretically, the copyright has expired by now.
Regards,
Pete