Nothing at all wrong with the 45/70 in my #1, it's just that I have always wanted a single shot in 450NE and this is the only way I can afford one.
I have a .500BPE double but as a single shot collector, have always wanted one in one of the large British rounds and the .450 has always appealed to me as being the first smokeless sporting cartridge.
Not a matter of need as I will never hunt anything dangerous just a matter of about 50 years wanting one.
Have shot a #1 in .416 Rigby and found it very accurate and easier to shoot than my 45/70 due to the heaver barrel.
I have a 26" octagon barrel we are going to use and will take pictures when it is finished and range tested.
Dave