So the Airsoft gun has a rifled barrel (.223) and a chamber that will tolerate the pressure? I don’t think so.
What is is probably trying to do is put a real upper receiver on an air soft lower receiver.
The LOWER receiver on the airsoft gun can be modified to take the UPPER receiver of an AR.
Toy LOWER receiver.
REAL UPPER receiver.
All the bang happens in the upper reciever. Plastic lower receivers are already made in the U.S. GLOCK’s have plastic lower recievers/frames.