On truly heavy, thick skinned, game.....penetration and lethality become nearly synomomous. The "rule of thumb"....if such a thing exist.....I believe goes something like this. Elephant and rhino....solids only. Wild bovine (in nearly all guises) first shot premium expanding, (for lung shot), backed up with all solids in the magazine or second barrel. On all other "furred" dangerous game, (great cats, bears, etc.), premium softs. For a balance of expansion and penetration. A soft will transmit shock more efficiently than any round nosed solid, and nearly any other shaped solid as well, but....only if it penetrates sufficiently to reach the vitals. There is some cross over of purpose with large flat metplats on large heavy dangerous game. (The heavier the game....as in the great bears.....the more efficiently those types of "solids" become. Because once again penetration and lethality are more closely related.) Some of the hard cast "large metplat" bullets (such as Buffalo Bore) are not true solids......as they are heat treated to upset some....but minimally. So energy transfer is trasmitted more efficiently but with as little as possible at the expense of guaranteed sufficient penetration!

And of course as was already mentioned, there are certain other instances where "solids" may be preferable. Fur bearers, medium to large calibers on small game, (ie. .38 Special kills rabbits well with no expansion......or a mid-range cast bullet load .30 caliber rifle for turkey where legal....would be but two such examples).

One other consideration in reference to the first paragraph above. With truly heavy game......elephants, rhinos, etc. Nothing fired from a human shoulder is going to overwhelm those animals with "shock" on a lung shot for instance......like a .270 Winchester does a whitetail. And nothing short of something fired with the pull of a lanyard......could. For animals that size a solid through the brain will instantly stop......and a shot through either heart or lungs will kill. But a shoulder shot elephant will die from hemorrhage and wound trauma......not by being overwhelmed by shock! On those animals lethality and penetration are one and the same!

And of course.....one other time I'd always choose a solid! When the caliber at hand is marginal for the task. A great example is the .44 Magnum in Big Bear country. The .44 Magnum with any soft point may not be certain to get enough penetration in Brown Bear territory to reach the vitals. When I carried a S&W 629 4" in Alaska I kept it loaded with 328 grain Hard Cast lead. I was not willing to gamble that I could achieve any bullet upset, (expansion), and still be certain of having sufficient penetration. Under those circumstances I compromised and settled for guaranteed penetration. The bullets I carried had demonstrated to me that they would penetrate.....period! I had shot a frozen 15" birch stump with that same .44 using 240 grain soft points. Those bullets all came apart after only 3" to 4" of penetration. The 328 grain hard cast bullets shot through the entire 15" of stump.....and were recovered about eight feet deep in the snow bank behind it. Except for the "rifling" engraved on the bullets......there was no upset. They could have been relubed, reloaded, and fired again! A .44 Magnum handgun is marginal under the best of circumstances on the great bears. And I was not willing to sacrifice penetration......for expansion!

Having said all of that.....anything on the face of the earth could be killed with a solid. But it isn't always the best choice......nor is it legal in many localities.....as was already stated as well!

Dave

P.S. As a side note......one of my "camp....and packing guns" in Alaska will be the 1895 Guide Gun SS loaded with Garrett cartridges. I would trust that rifle and load in big bear country emphatically! (As importantly.......if I have 60-80 pounds of meat, hide, or head on my back. I don't want a 10 pound rifle in my hands! Would be fine on flat surface roads and trails.....but doesn't work well at my age.....going "cross tundra"!)