could you kill a elephant with a .530 diameter 230 grain musket ball? / 570 diamter 278 round ball at 1200 fps ?

Of course it could work.
Historical interest or facts known?
Current-day poaching?

Slip one between the ribs into the lungs.
Then go into evasion mode.
A perforated lung on the other side at next opportunity would be next priority of the "hunt."
Eventually blood loss and pneumothoraces may deprive the CNS of oxygen enough to put the lights out.
Not recommended, but maybe better than a machete to the achilles tendons of the tusker.

Walter says he used to have a "buff body":

Had two clients take elephant with flint lock's and 5 with cap locks (and Mini Ball/maxi Ball)

Your ball weight is fine but the MV is a bit low...need to look at 1700-1900fps for a side heart shot on a bull.

Ganyana, those ele hunts with MLs, would be a very interesting read. Have you ever written about them?

Mad Dog

well my intention was thinking about loading this as buckshot, or a heavy tri-ball load 3- 60 cal 300 grain lead balls . in 10 ga or 8 ga

Mad dog..Both were bulls, not much to tell, snuck up..flash , fizz ...bang...flopOnly difference was a half second heart stoppage between the flash in the pan and the ball hitting home. In both cases the bull looked up but that was as far as he got...

The flintlock on lion was a little too exciting and is best told by a photo of the clients underpants hanging on a thorn...but since he frequents this forum I'll let him tell the story of a great bull hunt and an exciting lion one. 10g Double flintlock rifle- exquisit piece of kit.

Ganyana: Hope your mystery client responds. I want to hear more about the lion, the flintlock and the underpants ...