User involvement is essential for aligning software systems with organizational needs in agile development; however, achieving meaningful engagement becomes challenging in large-scale settings. Large organizations may contain distributed teams and diverse user groups whose limited availability and unfamiliarity with agile practices hinder sustained involvement. Although participatory and user-centered approaches work in smaller contexts, they are challenging to scale, leaving a gap in how to organize user involvement across dispersed organizations and multiple development teams. To address this gap, the present study examines pilot testing in a large-scale agile environment. Drawing on a qualitative case study of a Norwegian public organization, based on interviews with 35 participants from development and user groups, the study defines iterative pilot testing as a scalable practice in which unfinished yet operational solutions are refined gradually through user involvement when functionality is novel or complex. The study demonstrates how this practice can make development work more visible, enable development teams to be closer to their users and their work practices, and facilitate teams in navigating cultural and functional differences, thereby strengthening user involvement in large-scale agile software development.