All right I was actually studying some stuff for work and have deliberately been trying to avoid wasting any time on the net. But now you rotten SOB's have gone and done it and I am going to have to waste some time!
So here's my take on this.
First off the original question the S&W .500 vs .45-70. The hottest load I can find for a .500 S&W is the 440 gr Corbon @1625 FPS That's a pretty hot pistol round no doubt. And it's a pistol round. Like all handgun rounds it suffers from a severe lack of powder capacity and it will never be a pimple on a center fire rifle rounds behind.
Does that mean that the S&W .500 out of a rifle wouldn't be a cool little blaster that would be perfectly awesome for close range hog and even black bear hunting? No it doesn't not in the least. But whoever said that the .500 S&W would be a better choice for African dangerous game needs to drop his crack pipe and proceed directly to the nearest rehab center. The .500S&W on dangerous game is a stunt. The round even out of a rifle is hard pressed to make 3,000 Ftlbs at the muzzle (very hard pressed) not mention the 4,000 ft lbs required for thick skinned DG hunting in almost every African country that allows hunting. And it is highly recommended that you use a bullet that has a minimum sectional density of .300 or greater. And that brings us to the fabled and often spoken of .45-70.
Here are the facts.. Did you guys ever used to watch Saturday Night Live when they had the skit called "the gay, communist, gun club"? The shtick was to get into the club you had to gay, a communist and like shooting guns, no exceptions allowed. Well in Africa there is a another club kind of like that but it is called minimum legal requirements to hunt thick skinned dangerous game. And to play in that club you must have the following prerequisites no exceptions allowed.
1. A minimum bore diameter of .375. Or in Zimbabwe 9.3mm (.366).
2. A minimum muzzle energy of 4,000 Ftlbs at the muzzle or in Zimbabwe 3950Ftlbs.
That's it, pretty simple huh?
Now lets see if our fabled .45-70 is able to join the club
1. Bore diameter .458..Check!
2. Minimum muzzle energy of 4,000 Ftlbs..Whoopps!!
Even the hottest Garret loads don't make it.
Now I know we are going to jump all over me because of the penetration issue. Yes the .45-70 with heavy hard cast loads penetrates very well. Yes there has been a number of African DG taken with it. Yes those who did it were doing so illegally except for Mr. Vince Luppo who did his amazing feats inside a high fenced game farm in South Africa
which made it legal to hunt with his .45-70. And yes the .45-70 is capable of cleanly killing a variety of DG with the right loads as is a .50 Cal muzzle loader based on the same principles.
The .45-70 however can not be relied on to adequately penetrate on a frontal brain shot on a
BULLelephant as has been proven by several PH's who shoot a lot of elephant . Which makes it a very marginal weapon to carry in real life no BS DG country.
Randy Garret sells ammo in particular he sells .45-70 ammo he has a vested interest in promoting his product, keep that in mind when you read his "scientific" studies. For years people have been touting the test where his 530 gr HC out penetrated a .416 Rigby. Of course the .416 was using a soft point expanding bullet. The other thing that Mr. Garret conveniently likes to leave out is that often the faster round haven't stopped penetrating rather they've left the medium earlier IE they went off course and exited. And in those tests it's usually a round nosed bullet verses a flat nosed in the .45-70.
I've personally seen a round nosed Woodleigh 400 gr out of a .416 Rigby enter the hind quarter of a big bull cape buff smash the hip and exit out the throat. Is that enough penetration for you?
In a .458 Lott I've personally shot buff up the rear and found the round nosed solid bullet under the skin of the neck. That's a good solid eight to ten feet of penetration. a .470 NE does about the same. the last buffalo I shot with a .470 I hit with a 500 gr X Bullet in the on shoulder I found that bullet under the skin in the opposite hip.
There was a test done on a device called the iron buffalo. It is series of Plywood boards inter spaced with water compartments. In that medium which is set up to more closely approximate the density of heavy animal tissue and bone the higher velocity .458's with similar solids in similar shapes absolutely smoked the lower velocity .45-70 rounds. The frontal brain shot tests on a wet big bull elephant skulls with the .45-70 tend to bear this out.
In summary here's my take on the .45-70 on Dg issue. First off the myths.
"The .45-70 in a modern loading can nearly approximate the .458 WM"
B.S! The .45-70 with a 400 gr load can get close to what a .458WM will do with a
500 grload apples and oranges guys. The .458 WM is an honest 5,000 ftlb round a true stopper. the .45-70 can eek out an energy level somewhere in the mid to high 3,000 range and with total thermo nuclear load in a Ruger Number one you can just get it to edge 4,000Ftlbs with a 400gr bullet which of course is seriously lacking the SD needed for true reliability on DG. With a 500gr bullet a .45-70 can't carry a .458's panties to the laundry. Not even close.
"The .45-70 will out penetrate a higher velocity .458 mag"
B.S again all of the "tests" have been either a solid with a square nosed profile out of the .45-70 verses a soft point expander in the .458 mag or it's been with round nosed bullet. And it's been in a medium that would benefit from lower velocity like wet paper or water cans not one that truly tests the bullets ability to penetrate a medium that replicates the structure of an animal like an elephant. To really get a true test of penetration the following needs to be done. A series of bullets needs to be fired into a variety of mediums. The bullets need to be of similar shape a construction and the shooters need to be non biased and competent so that one round isn't accidentally started off at slight angle to skew the data. If one round does veer off and exit that needs to be taken into account and either re fired or found to see why it did so.
I've killed a lot of game with .45-70's with all kinds of bullets from Garret loads to regular old Remington 405 gr soft points. The .45-70 is a smasher on lighter game no two ways about it. Even on heavy game it is a very efficient killer with the right loads. But in my experience it doesn't even come close to the effect that a true heavy like a .470NE has on game. A .470NE hitting a big feral hog is a sight to behold it hits with extreme authority it absolutely crushes them to the ground. A .45-70 with the hottest loads simply doesn't have the same smack.
Here's something for you to mull over, I can always load my .470NE or my .458 Lott down to 1500 fps with a 500 gr bullet but can never in your wildest dreams load your .45-70 up 600 to 800 FPS to match my .458 Lott.
In closing is the .45-70 capable of killing DG? Of course it is so is a .303 or an 8MM or whatever given the perfect situation. Is the .45-70 a true DG caliber? Not only no but not in your wildest dreams should it be considered as a serious choice in DG country and in particular in elephant country. I have never met or do I know of any DG PH's who would carry one professionally as a stopping rifle with clients present. That statement does not include several South African game farm PH's who carry them, once again apples and oranges.
There you go that's my take on it.
PS
Do I have a problem with anyone hunting DG or carrying a .45-70 in DG country. Nope not in the least. It's your dime it's your time go knock yourself out. And if you really want to try it out go do it then come back and tell me all about it until then it's just a comic version of the truth.
I am also having a .450-400 double built as we speak and my back up "light" rifle in DG country is a .375H&H. Which is minimal yet adequate and legal for DG.