kuduae,
Thanks for posting and a very good description of this DR operation. That is an interesting design concept.
Also interesting that they would chamber the barrels differently. It means that when one is hunting in the bush, they have to carry two different bullets, and during a stressful, emergency situation, pull the correct cartridge to reload. Seems complex & subject to error.
Chambering DR in two different calibers seems to not be unusual in continetal guns. I have seen a few DR with one barrel a medium bore and one a small bore.
However, in medium bore and large bor rifles, I am not sure I appreciate the logic. I saw a very nice looking Collath DR with one barrel chambered for the 10.5x65R and the other barrel chambered for the 9.5x65R. I believe both were old balck powder rounds that evolved into nitro rounds but could not imagine there being that much difference between the two.