Yes.
It will depend on who is making the receiver.
Never deviate from published reloading data. You risk injury or death if you do.
The 475 Nitro is a low pressure cartridge. The 460 Weatherby is a high pressure cartridge. They use different powders. No, you cannot reload a 475 Nitro to 460 pressures because a gun chambered for 475 would not take the higher pressure.
There are several, such as the .600 Nitro Express and .700 Nitro Express, not to mention anything considered a cannon.
I think large, heavy, expensive, custom made double barreled rifle. To the best of my knowledge, there was one handgun made in .600 Nitro Express, more as a curiousity than a usable handgun.
Yes, here's several. .585 Nyati, .600 Nitro Express, .700 Nitro Express, 14.5x115... then you have weapons classed as cannons (20mm and up). The .50 BMG/12.7x99 isn't even remotely close to being the largest cartridge out there.
Rather than a sharp angle at shoulder and neck, Weatherby cartridges have a curve. This was done for a smoother flow of the gasses from the burning powder, and as you note, is a characteristic of the Weatherby cartridges.
Eldar Kai makes the powers of someone 10 times stronger than what they already are. Another way to express this would be to say they're tenfold times stronger than they originally were.
S&W .500 magnum. how about the 45/70 revolver ??? or the 600 Nitro Express
Way back when, rifles were made to use black powder. Newer technology came into being, with Smokeless Powder, which is based on Nitrocellulose (guncotton) and Nitroglycerin. These new guns had more power than the old black powder. To impress customers with the idea of the increased power, many cartridge makers incorporated the term Nitro and/or Express (a very fast train) into the name of their cartridges- like the Holland & Holland .600 Nitro Express. (Ummm- yes- new and improved- gotta go buy one. )
It can only safely accept the 270 Weatherby Magnum if that is what it is chambered for. If you want to chamber it in some other caliber than get a new rifle. Just because two bullets have the same diameter bullet (270 or any other caliber) does not make it safe to fire it in your gun.
There is no such cartridge as a ".308" weatherby, only a .308 Winchester, interchangable with the 7.62 Nato. Once upon a time, Weatherby only made rifles in unique weatherby cartridge calibers, eg. .300 weatherby, .378 weatherby, .460 weatherby, etc. Now weatherby makes rifles in many non-weatherby cartridge calibers, including the .308 Winchester. Do not confuse a rifle manufacturer with the company name that may have introduced the cartridge in which the rifle may be chambered. To further get your head spinning, many cartridge companies make cartridges (all equivalent) in the .308 Winchester caliber including Winchester, Remington, federal, norma, and multiple European companies. The short answer is yes they are the same. If you see a weatherby rifle chambered in .308, (and not .308 Norma Magnum), it is a .308 Winchester caliber (Winchester rifles exist in .308 Winchester caliber). The weatherby rifle is most likely a weatherby 'Vangard' model (a cheaper line of rifles manufactured by weatherby). Top of the line weatherby model rifles are noted for their high prices, ornate stocks and high power weatherby calibers (the .460 weatherby magnum is the most powerful factory cartridge in the world, about 80% more muzzle energy than the .458 Winchester magnum, first sold in Winchester's African model 70 rifle).