FN-FNC Stock Adapter Type 2 # SA-FNC-02 FN-FNC Stock Adapter Type 2 (SA-FNC-02) $50 FN-FNC Stock Adapter Type 2 allows any Ar-15/M4 stock to be used on the Belgian FN FNC. The adapter is easily installed by removing the original stock and bolting this adapter in its place. No permanent alterations to the rifle.