Reloading for the 400 is not easy...
I guess as a 400 Whelen owner who has reloaded a lot of 400 Whelen, I have to ask, how so? How is it more difficult than any other round to load? Perhaps a couple more steps if you're forming cases from 30-06 or 35 Whelen. With Quality Cartridge brass, which is 30-06 cylindrical with a 400 Whelen headstamp, simply run it into the die, trim to length and load. Same applies to Norma 30-06 cylindrical if you can find it.
With 30-06 or 35 Whelen brass, it adds a step or two using an expander die or fireforming with COW. I've done both. Neither are difficult. A little time consuming but not difficult.
