Not that it matters a lot but just to keep the facts straight.
Arne who owned CSS was shooting a 6.5CSS before Alexander started messing with the Grendel. The guys at Lothar Walther USA introduced Bill A and Arne. Arne, Bill and Lothar worked together on things. Bill A trademarked the "Grendel" name.
les Baer entered the picture much later, around 6 years later and the 264 LBC name was born.
There really aren't that many companies making the 264 LBC barrels. Lothar could have done them no doubt. Black Hole or Satern could have also.