German metallurgy and lost industrial memory

If Germany built a copy of the Japanese 410 mm gun as a built-up weapon, how much weight difference should be expected?

The weight might be slightly lighter, but the more important issue is different performance because German metallurgy and industrial memory had been weakened by the interwar construction gap.

A German built-up copy of the Japanese 410 mm gun might be slightly lighter, but weight is not the most important uncertainty. Museum examples of German armour point to a decline in metallurgical quality after the First World War. The long interruption in major warship construction dispersed skilled workers, retired experienced specialists, and allowed unwritten shop knowledge to fade before the Deutschland-class program began rebuilding capability. A plausible paper design could therefore deliver different performance because industrial memory and production quality were no longer the same as in the Imperial German Navy.