South Korean Airsoft YouTube channel, Airsix TV, does tuning services for local players and in this video they show to do tuning of the Marui M&P9 PC Ported GBB Pistol... "It is a corner that shares the tuning and repair details of the airsoft gun you own, and suggests tuning directions and solutions for possible damage in the future.

If you entrust your favorite guns and history you want to show off to us, we will show you the tuning details, repair details, and what kind of repairs to do, and we will show off on behalf of the client."