The 333 Jeffery and 280 Jeffery are based on the shortened 404 Jeffery case.

The 350 Rigby is basically a unique case. It is smaller in head diameter than the 416 Rigby. It can be made from 375 Flanged Magnum brass, but requires extensive modification including removing the rim and cutting a new extractor groove.

Off the top of my head I can't tell you much about the 280 Halger, the Halger line of cartridges was considered pretty hot in their day. The name comes from combining the first part of the names of their two creators, Halbe and Gerlich.

Jim