As a side note: (I add this separately because I don't own one).
A 4 bore (bore is the same as gage in this case, meaning how may round balls of the diameter of the bore (or gage) it takes to make a pound. A 4 bore would be 4 balls to a pound, a 12 bore (12 gage) takes 12 round balls to make a pound.
I'm re-reading "A Hunter's Wanderings in Africa" by Fredrick Courteney Selous, originally published in 1920 but takes place in the latter 1800s.
Selous was an ivory hunter using, among other guns a 4 bore, that is 1/4 pound of lead, or 1750 grs. That puppy kicked at both ends, but wasn't effective as the modern African cartridges, mainly do to the lack of velocity. Those old ivory hunters had get withing bad breath distance to those dangerous critters. Not to mention the recoil would be worse even then my 416 Rigby.
Just thinking about it makes me want to go hug my 257 Roberts.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071