If the Germans were ever to catch up to the British it would have happened long before WWII. A great many German makers built double rifles in those days. You have to remember that driven game shooting has always been more common there than in Britain. I've handled a great many of the pre-war German double rifles over the years - dozens of names - Merkel, FW Heym, Simson, Bock, Sauer, Geyger, Schwimy, Foerster, etc. Some of the workmanship was to a very high standard, but style was usually heavily Teutonic. Yes, some of the engraving is incredible, but so is some of the British.

Like the British, the Germans largely held to their own specific "formula" for their sxs double rifles, and still do. They've always favored very slender actions. Since most of their double rifles were intended for the driven game of western and central Europe, most were medium bores, and the slender profile worked OK for these. However, the heavy caliber rifles had to have very little profile to the barrels to get the weight up to a reasonable level, resulting in a finished rifle that swung like a post. I've encountered a few refreshing exceptions along the way, but they're rare. The British used larger actions and more barrel profile, which put more weight between the hands and improved handling dramatically. I believe that this is partly why the British dominated the large bore double rifle market for the duration.

I remember the first large bore German DR I ever handled - a Merkel boxlock .500/.465 from the '30s. I hadn't owned a double rifle yet then, and was looking at everything with an open mind. The workmanship was high quality, and the Teutonic flavor unusually subdued. It was a lovely rifle in high condition. I remember describing it to a friend as the first "bull barreled" double rifle I had ever seen and would still describe it that way today. It handled like a brick.
--------------------------------------------------------------------------