Always fun to have something folks don't see every day. The .400 Whelen would be that...………
The hang-up I see is you either shoot bullets designed for the .405 Winchester or you pay $1/each for higher end custom stuff like Hawk bullets. IIRC, Qual-Cart makes properly head stamped brass for about $2/each.
Kinda a spendy number when there's other rounds that would do the same thing or more for less $$$. But far be it for ME to lecture ANYONE on loading for and shooting off-the-wall, money hungry guns.
Go for it !!!