No rest for the wicked!
Greener's work, 'The Gun and it's Development 9th Edition", which I was given a copy of back in '76, became my inspiration for working with double 12 bores and round balls. With a bit of work, I was able to beat Greener's diagrams by a considerable margin, and used the round ball double for deer the first time in about '83. Friends of mine then used the patched balls in their duck guns, (ball and patch easily passed through the chokes with only .002" compression per side only) for moose while they were duck hunting.
I've never shot a moose with my 12 bore shotgun, however I have some heavily patched 15 bore balls loaded up for the double barrel Husky at his time, ready for fall grouse hunting. At 30 yards, they do better than bare balls did from the gun's straight rifling, cutting a 2 1/4" hole for 8 shots. Note the Husky is 16 bore only in it's choked left hand 'shot' barrel, while the right is 13 bore straight rifled. That's the barrel I shoot the patched balls from - a 15 bore ball with a .025" patch.