A couple of thoughts.

1. Stopping Power when used by Taylor, etc, in the discussion of big bore rifles = stopping a charging elephant with a solid bullet, even when the shot misses the brain. But there are other uses of "stopping power", for example handguns and body shots. So defining Stopping Power, as mentioned, is critical.

2. Solid bullets have varying shapes which produce different results. The most reliable in the scope of Taylor and elephants, etc, until relatively recently, was the hemispherical round nose. Today we know its the truncated cone flat nose, with a wide meplat. Worst was the old style 470 bullet with a progressive ogive and pointier shape than the hemisherical round nose, too often veering off course.

3. Energy has a direct correlation with penetration when discussing solid bullets. For example, if two of the same bullets are fired, one at greater velocity, and so with greater energy, the one that is faster and has more energy will penetrate further.

4. Energy has a more or less direct correlation with stopping power, stopping power defined as stopping a charging elephant. But momentum is the better measure since bullet weight is more significant than velocity, given that velocity is "sufficient."

5. Limiting the discussion to solid bullets and elephants, it's really remarkable that the Brits got it very right about 110 years ago when they defined the parameters of successful cartridges for braining elephants to be SD +/- .305, V +/- 2150fps.

6. Hopdoc is right, a table of cartridges of ascending stopping power, as defined by stopping a charging elephant, can be easily put together. Taylor has already done it. His table, when corrected for errors and for real, in the field velocity, and updated with newer cartidges is pretty good. Ignore the "knock out" predictions and substitute "knock down" or "turn a charge" and his table is very predictive, according to over a century of real experiences.

But when you move into more variable areas, like softs and body shots, there is going to be some SWAGing going on. Taking a whitetail deer as an example, a pretty poor bullet is actually more likely to "stop" a deer with a DRT than a good bullet that will produce a dead deer more reliably, but with less drama. Take a Ballistic Tip and a Partition for examples.

Hopdoc, take a look at Taylor's KO index and his tables of cartridges and you've got a pretty good heiarchy for stopping elephants.

JPK