Cartridge Name Help??

[750k2]

Anyone know by what name the 7 rem mag necked down to 257 goes by??
No blow out just a simple neck down.
And if you know of anyone who chambers for this round??

 

[2644ever]

The .257 Weatherby is so close, I can't imagine why someone would choose the custom option... plus the reamers and the dies are already available and cases could be made out of 7 Rem Mag too.