Heres how I do it:
First with it all apart like this:
The barrel goes in first, the barrel has a line that marks the bottom this line should be pointing down.
After the barrel is in the smaller piece on top goes next. Put it in togeter like so:
With those steps done you can put the hop up dial on and then the c-clip to hold it together. Finally install the brass ring and spring(not pictured)
Pay attention to how the cut outs on the side of the barrel are alinged.
to get the barrel and hop back on the gun you need to line up these posts on the hop:
to these on the barrel assembly/fuse holder:
Once they are lined up push the hop unit in and then turn it (if it doesnt lock try turning it the opposite direction). It should lock into the barrel asssembly and be ready to go. :tup: