I've removed the bi-pod from the gun to make it easier to take clear pictures but it is not necessary.
Pull the cocking handle back to free the gas piston from the gas tap on the barrel.
On the left side of the receiver there is a stud locking the barrel in place. Press this and twist the barrel.
The barrel is now free to be pulled out.
Receiver and barrel
Let the bolt go forward and unscrew the holding pin on the right side of the receiver, located above the trigger.
Hinge the stock down, I give the stock a tap with the heal of my hand to get it started.
Turn the receiver over and locate the leaver on the bolt carrier/gas piston.
Lift the leaver up, applying some forward pressure.
The bolt carrier/gas piston now slides to the rear out of the receiver.
Bolt and carrier, unlocked
Close up of the bolt and carrier in the locked position.