This is the Autococker Barrel Adapter for the CCM SR1 first strike rifle.  The adapter is specifically designed for the single-shot, shell fed SR1 and allows for the use of SR1 shells with any autococker threaded barrel.  This adapter also features external threads for mounting handguard delta rings. 

   CCM products are designed and manufactured in the United States and are machined from high quality materials such as 6061 air craft grade aluminum, 300 series stainless steel, and durable plastics such as delrin and lexan.
MADE IN THE USA