The efficiency of using strategic projects to accelerate long-term change is questioned, especially in interorganisational contexts. Strategic projects operationalised in inter-organisational contexts are decoupled from the parent - permanent - organisation, creating a need for project actors to manage in-between. The aim of this paper is to increase the understanding of practices for managing strategic projects in inter-organisational contexts, initiated by public client organisations. Applying a practice perspective, this paper presents a case study exploring a strategic project to test collaborative contracting in road maintenance contracts for a public infrastructure client in Sweden. The findings revealed a lack of structure regarding both participation and responsibilities, as well as uncertainties and ambiguities with respect to the goal of the strategic change. The study shows how strategic practices move from central units at the permanent organisational level to the contract level where the strategic project is operationalised and tested, isolating the project and making project actors act as middle managers in-between the project and parent organisation. Thus, the study contributes with a discussion on the efficiency of strategizing through projects in public organisations, especially those operating in a network of suppliers through outsourcing.