Disassembly

1. Make sure the gun is not loaded or cocked, and the magazine is removed.

2. Using a paper clip or your fingernail pull back on the mainspring housing (Fig. 1 red arrow).

3. Swing the main spring housing out of the grip (Fig. 2 red arrow).

4. Pull down on the hinge of the main spring housing and  remove the housing from gun (Fig. 2 blue arrows).

5. Remove Bolt (Fig. 3 blue arrow).

Reassembly

1. Locate on the underside of the barrel the front-most hole in the barrel and line it up with the hook on the grip (Fig. 4 red arrow) with the hammer flat (Fig. 4 blue arrow).

2. Slip the barrel over the hook and pull back on the barrel while pushing forward on the grip (Fig. 5 red arrows).

3. Insert bolt with spring facing up (Fig. 5 blue arrow). MAKE SURE THE FIRING PIN STOP IS IN THE BOLT!!!

4. Flip the gun upside down and pull the trigger.  This gravity will make the hammer fall to the uncocked position. (Fig. 6 red line hammer is cocked, blue line hammer is uncocked)

5. Flip the gun right side up and insert the main spring housing (Fig. 7 blue arrow).  It is all the way in when it appears at the top if the barrel (Fig. 7 red arrow)

6. Make sure the hammer strut is leaning against main spring housing when you rotate it back in (red circles).
  

7. Lock the main spring housing in place.