Interesting. You can see why I was confused. It is logical that this entire rifle/cartridge combination was a RM&M (Dreyse) product. As Lancaster says, these rifles are similar to the M71 Mauser, and were often marketed as "Mauser" rifles.

The cartridge catalog illustration raises another question: What is the Model 88 6.6 cartridge illustrated? I can't seem to find one in my literature.