I believe the 457 is referencing the 457WWG cartridge, invented by Wild West Guns
I had a horrendous experience with those people back in 2004-2005...... I sent a gun to be converted to 510 Alaskan, when it came back it was awful.... First they said about 6 months. Ok, no worries, at 8 months I called, not ready yet. OK, at 10-12 months I called, its ready, but we don't have a box to ship it in!!!!!! Yeah, can't ship because they don't have a box? Finally I got the rifle, and it would not even chamber a 510 Alaskan (50 Alaskan at .510 caliber) Rough as a corn cob, awful looking, just terrible. I had just started working with JD at SSK, and had a good positive experience, so much so that I would not even send the gun back to WWG.... I wanted ZERO to do with them at this point. I sent the gun to JD so that they could at least run the reamer in and get it to chamber, they did, touched it up some and got it back to me in good working condition. It had Wild West Guns scratched on it, and I was so aggravated at that point I got rid of it, never even fired the damn thing. And did not want it in my sight. End of story. I also suspect they have actually not done much study on their cartridges, pressure data and such.
TV hunting shows...... I want to puke, so much for that. I quit watching that drivel so long ago I can't even remember........ Stupid crap.
Now for a lesson in physics...
375H&H 300 grain bullet at 2500 fps is 4163 lb-ft with a SD of .305
457WWG 350 grain bullet at 2300 fps is 4111 lb-ft with a SD of .238
So in reality he's using a rifle to backup hunters on DG that is less powerful and has a lower SD than the minimum required for a traveling hunter.
Well, first of all, for any actual real comparison, I damn sure would not have use that Rat Cartridge/Caliber... (375).......
Believe it or not, caliber is extremely important in the field and there is a hell of a difference between .458 and .375....... If you use todays Modern Bullet Tech, I will take the lowly 45/70 over a rat caliber every day of the week, I wouldn't use 375 for prairie rats, useless good for nothing cartridge/caliber.
But if you make a proper comparison, say 458 Winchester, then you make a good point in many ways.
As for the SD factor, that is not a viable factor considering todays Bullet Tech. SD will only be a factor when all other factors considering bullet design are exactly the same, along with external factors such as velocity. Other than that, SD is not very important. This applies to both modern trauma inflicting bullets such as Raptors, Maximus, Hammers, and even more so with Solid Bullet design.