The Kaw Valley Precision 6 Position Mil-Spec Stock Completion Kit that I would recommend for a 9mm PCC is MPN:KVP-MilspecKit-5.4 (5.4 oz). This is the heaviest kit available that will allow for proper functionality for a 9mm PCC as they require much heavier buffers (between 5.0-8.0 oz) in order to properly function.