LXV Designs put out video showing how to put together their Carl Gustav for airsoft use... "A great Swedish launcher has been brought to the airsoft world! This adaptation does not function in the same way as the real counterpart rather it is made to become a beautiful and functional airsoft grenade launcher. It is made for a 40mm airsoft grenades by using self made adapter (I do not provide an adapter as there are many different kinds of grenades and I cant make a single adapter for them all). This means it can launch anything including the well known Taginn rounds. It is a fairly challenging build and I would advise to have some previous experience building similar projects.

In this video I go over the assembly steps of the LXV Airsoft Carl Gustav. You can find the stl and assembly guide in here."