According to Barnes manual, their 570gr., 50cal bullet for the Nitro Express has a SD of 335. It matters not if it is hollowpointed or round nose, the SD remains the same & comes from the same formula - mass and calibre. Their listeing for all .375" and 6.4mm bullets are correct, so I don't see why the .50's would be in error.
: Did you use .510 as the calibre?
: The BC is the one that changes with bullet shape.
: BTW - in a .50 ctg. of enough velocity, even a 450gr.solid bullet would have sufficient penetration to make the off side of an elephant's brain. My .69 calibre muzzleloading rifle does, with an alloy round ball propelled by 165gr. 2F at 1,550fps., Samual Baker, a man of immense experience, said it did. I don't really see a need for a 600gr. bullet in the .50. The .476 Nitro, almost .50 cal uses a 520gr. With a .476Nitro Elmer Keith went his entire safari using only the right barrel - or was it the left. He shot a couple elephants, cape buff and rhino with the rifle - all single shot kills, using solids every time. I expect the suggested formula may be necessary if you are lacking in bullet diameter, with say, a .450/400. There, the energy level and SD are vital.
: As such, the .50 ALaskan isn't an African ctg.,however, loaded for bear, as Harold Johnson did, it would probably make a surprising account for itself, if used there. Complete penetration, and exit from lengthwise shots on coastal Brown bears, might have enough penetration for most game found on the big continent. He used 450gr. cup-point solids.
: I don't remember for formula off-hand and couln't find it - so would you post it please?