When a defence production line stops, the question for a ministry is rarely whether another European factory owns similar machines. It is whether that factory may lawfully use the design, has been approved to make the part, can be called on to produce it at a defined moment, and will have its output accepted. Each of those conditions is normally held by a different party: the owner of the technology, the customer or prime contractor that qualifies the process, the firm that controls the capacity and the authority that accepts the product. In March 2026 Germany’s competition authority cleared a joint venture in which Diehl Defence is to manufacture 155 mm artillery ammunition in Germany under intellectual property licensed by the ammunition’s developer, Nammo. In December 2025 Patria announced contracts with Germany for up to 876 Patria 6x6 vehicles whose production, according to the company, is being transferred progressively to German industrial partners. Neither arrangement is publicly described as a reserve that one site can call on when another fails, and neither discloses who would pay to keep such a reserve ready. The issue for European rearmament is therefore what has to be in place before the capacity of another European producer, including a competitor, can be counted as continuity rather than as nominal capacity.