A proof-of-concept practice-based implementation network was developed in the US Departments of Veteran Affairs (VA) and Defense to increase the speed of implementation of mental health practices, derive lessons learned prior to larger-scale implementation, and facilitate organizational learning. One hundred thirty-four clinicians in 18 VA clinics received brief training in the use of the PTSD checklist (PCL) in clinical care. Two implementation strategies, external facilitation and technical assistance, were used to encourage the use of outcomes data to inform treatment decisions and increase discussion of results with patients. There were mixed results for changes in the frequency of PCL administration, but consistent increases in clinician use of data and incorporation into the treatment process via discussion. Programs and clinicians were successfully recruited to participate in a 2-year initiative, suggesting the feasibility of using this organizational structure to facilitate the implementation of new practices in treatment systems.