Google Maruzen AP SR2 takedown.
The MB06 is a clone of the Maruzen AP SR2.
Remove the three body screws; two near the trigger, on beneath the barrel ring. Slide forend (the part the magazine goes into) forward and off. Remove the stock by opening the back end of buffer tube and removing the screw holding the tube in place. Punch out pin in center of body. Having done that, THEN the receiver/barrel should hop right out for you. If you're still having trouble I'll post a picture guide
Good luck! They're pretty simple once you do it a few times, but they're definitely more complex than most spring bolt rifles you see around.
EDIT
DON'T go twisting your outer barrel...