Don't know that one, is it new or a long lost cartridge? The trouble with building a long range thirty is that the selection of 200 grain and above bullets suitable for those kind of distances is limited. Be careful about going straight to full copper construction bullets because the velocities at extreme distances can be low enough that the copper bullet may not expand well. Berger bullets are getting the nod in some circles for this type of shooting.
It is a fairly new cartridge and is loosely based on the 416 Rigby case. Built off of the .338 Norma.
Copper bullets expand at almost all velocities. Back in the day they had trouble but not know. Berger is getting good and bad press. His BC is good. Barnes has come out with a new long range bullet that is seeing good press as well. In 30 caliber, it seems allot of the serious long range hunters are using the Nosler 200 grn AccuBond which has a 588 BC.
The 30 Caliber is becoming very, very popular among long range hunters...go to snipers hide and check it out!
308 Norma Mag!!!!! Great rifle. My father gave me a cutom built one for my high school grad. Beautiful gun. I love it. I'm sure u will too. Can't wait to see it. Only downside is that ammo is hard to find and a lil expensive. BUT!! Nothing u cant get from the great guys at Fine Firearms! ;D