Old thread but I picked one up in 2010 for the 9mm rifle. Finicky as all get out but it's an awesome PCC set up. Forgotten Weapons did two videos on their reliability and how to load it based off the spring tension. Very helpful.
You might check out Tippecanoe county fish and game club.
Core Briggs Dynamics up in Tippecanoe is also very good from what my friends are saying and are members there. They bring in instructors, he runs and guns, etc.