Correct me if I am wrong but I thought 9.3X64 could be made from .376 Steyr brass. I heard they are the same case with the .376 necked up to take the larger bullets. Also you might want to cantact Peter Cardona at Quality Cartridge. He can get you anything with the correct head stamp. He was going to do the .450 Vincent for me. It was about $2.50 for each round but they would of been formed, trimmed, and correctly headstamped. His e-mail is abn82d@hotmail.com and his web site is http://www.qual-cart.com