Looks a lot like a 404 based cartridge - which would beg the question - WHY?
404 is a .423" bullet - 416 is a .416" bullet. The only thing going for the 416 version would be better availability of projectiles I guess.
Looks like the rim may be a little more rebated than the 404 - not as much as a 425 Westley or an 11.2X72 Schuler though.