There is an article in an early issue of the German Gun Collector's journal about the design of this action. Looking at the way this locks up, and reading the article, it would seem that the design is incredibly strong and will take a long, long, time if at all to "shoot loose." I don't claim to be an expert in the area, but I would say it is far superior to the normal actions as, it would seem impossible to 'open' or work loose because of the inherent nature of the design.

The cartridges sit inside a carrier/extractor at the end of the barrel section of the action. When open, you place them into the carrier, and when the gun rotates 'back to battery' the bbl and action are locked together with the two sections held by what does indeed work like a bolt action lug arrangement, one where the 'lugs' are very deep, as shown in the photos above of the breech section. So, as I said, given the very strong 'bolt lugs' and the depth of the lock up (the depth of the receiver section can be seen in the photos, it runs the entire depth of the section ahead of the wood of the forend, just when it would 'shoot loose' would be beyond my shooting lifetime.

The article from GCA was, I believe, on line by Googling the name of the design, and explains it fairly well. If not, Mike at Finefireams has a lot of 'time under belt' on these and may be able to offer a better explanation. Dave.