Step 3: Reassembling the trigger box
Reassemble the hammer
Reinstall the trigger. Arrange the springs on both sides like in the picture.
Carefully insert this into the trigger box so that the front ends of the springs rest on the edges circled in the picture. This will probably take a few tries.
Once everything lines up, put the trigger pin back in.
Reinstall the hammer. You will need to move the lever on the right side of the trigger box (part 87) forward slightly to get the hammer in its hole.
Place the hammer into its place. Reinsert the hammer pin.
Next, reinstall the firing pin and firing pin spring. It is easier to work with the hammer cocked for this part.
Slide the firing pin spring onto its post, oriented like in the picture. It will be under moderate tension at this point. It is important to get this right, so I included 2 pictures...not sure which is clearer.
Replace the firing pin block lever (part 97) on the same post as the firing pin spring.
Next place the firing pin in so that the firing pin spring goes through the middle of the pin, providing tension towards the back of the trigger box.
The firing pin will be under tension; to hold it in place, SLOWLY release the hammer (remember to push the lever, part 87, forward in order for the trigger to release the hammer).
All the parts should be in. Replace the cover. You may have to fiddle with the valve locked and hammer pin until everything lines up. Note that the valve locker will have to be slightly depressed to let the firing pin fit through.
With the cover back on, replace the spring that locks into the firing pin.
And then the 2 screws. The hardest part is over! You now have a complete trigger box.
Step 4: Reassemble gun
Place trigger box in receiver
Replace the front pin.
Reinstall the pistol grip.
Reinstall trigger guard.
Reinstall the (new, steel) fire selector. Get it into its slot upside down, then rotate it down into position.
Place the safety lever back on the gun. It might be a tight fit; hammering it on may be required. If you find you just can't get it on tight enough, bend it slightly so it is firm against the receiver (I had to do this).
Once the safety lever is on, secure it to the fire selector with the screw.
Reinstall the bolt and return spring.
Close the cover, pop in a mag and test fire! Your sexy new steel parts should work flawlessly. There will be a break in period of ~1500 rounds to get the parts properly worn in. Also note that the bolt carrier is made of pot metal and wears against the steel hammer - this will be a source of continuous wear. Don't worry too much as the bolt carrier is a big piece of metal, but a steel replacement sure would be nice : P
Let me know how I did on this guide. If you liked it I might do more in the future.