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!