PlaSSO shows the GM6 Lynx Shell-Ejecting Airsoft rifle which is based on the 50 BMG Gepárd anti-materiel rifle. This is airsoft version is made in South Korea and one was first spotted last year. This was in use in the Soviet Union, Warsaw Pact and China. It is also used by Canada, UK and India.
Panverine demonstrates the home-made GM6 Lynx Gas Blowback rifle and man that blowback is fierce. This is based on the .50 BMG Gepárd anti-materiel rifle (also uses the 12.7×108mm round) and the M6 is the last iteration of the rifle and officially called the GM6 Lynx. This was in use in the Soviet Union, Warsaw Pact and China. It is also used by Canada, UK and India.
If you want a bullpup airsoft gun based a 50BMG gun, then this IWA 2022 - GM6 Lynx Semi Auto 50 BMG Bullpup featured by BB2K Airsoft may just be the one you want done. It looks like Bruce had an orgasm holding it... "There are things that you only experience once. In Germany to have the opportunity to pick up a GM6 Lynx. This dream came true at the Carpathia Global booth.