Judging by just the numbers, I might conclude that anything under a 577 NE is marginal to inadequate.

Also, as the RDP value doubles, does stopping power double? For example, does the 500 NE have double the stopping power of a 416 Rigby? Perhaps in a charge where the brain is missed it does, I am not sure. But I do know that a 500 NE is known for turning charges even if the brain is missed, while the 416 Rigby is known for not turning them.

This formula shows that formulas are often inadequate to describe terminal ballistic effects. A 45-70 driving a 405 grain bonded bullet 2000 fps has a RDP of 19.0. More than the 416 Remington, 416 Rigby, 378 Weatherby and 375 H&H. Perhaps it should be calculated with impact velocities.

There is no formula that 'covers all the bases'.

Pick one you like, and go from there.

I like Taylor's KnockOut table, but only for comparing big, modern (post-1900) cartridges.

George

I stopped reading when I got to: "Besides, not all bullet shapes such as flat-nosed solids for example, are available in all calibres or to all hunters."

Sometimes it pays to check what is going on on the internet once every ten years or so.

Gerard,

At the risk of piling on.... I had GW's safari rifles book but it was not up to snuff so I passed it on to someone who might not notice.