The article presents the results of studying the problems of fulfilling a comprehensive project on transforming a defense enterprise business model, mastering modern approaches to build production systems, including the concepts of lean manufacturing, “6 sigma”, CALS technology, and others. The ongoing reduction of the government defense contracts to the level ensuring the planned renewal of the army and navy armament requires an increase in manufacturing civilian products by defense enterprises to load the released capacity. The President of the Russian Federation has set the task of bringing the share of such products to 30% by 2025 and to 50% by 2030. However, the entry of these enterprises into the competitive market is not adequately prepared due to their lack of market competencies, the mastery of which requires significant changes in the organization of production, labor and management, or otherwise - transformation of the business model being implemented. The business model in the study refers to the conditional representation of the enterprise’s business, which allows us to understand the composition and interconnections of its elements, ensuring the creation and delivery of value to the consumer. In turn, the value approach focused on maximum customer satisfaction is contrasted with a conservative product approach to building production systems based on the priority of the capabilities of the existing production apparatus. The application of the modern concepts provisions for production and business modeling made it possible to identify features and to justify organizing the project for transforming the business model of a defense enterprise, mastering modern methods of constructing production systems, the composition and tasks of its participants, as well as the mechanism for consolidating the results of changes in the regulatory and methodological framework enterprises. Thus, based on the recommendations of the study, organizational prerequisites are formed for the successful diversification of defense enterprises, as well as the institutionalization of transformations of the production system in the practice of their work.