Its been a while since I did one. This is from memory.
1. Install the sight without the spring and roll pin.
2. Turn it to the lowest elevation. Lining up the slot in the sight stem where the roll pin passes with the through hole in the receiver.
3. Start the roll pin into the upper receiver but stop when the end on the pin starts to show in the spring tunnel of the sight base.
4. With the receiver upside down in a padded vise, drop the spring into the tunnel.
5. Compress the spring with a punch or dowel.
6. While the spring is compressed, tap (don't pound) the roll pin into the spring tunnel. This will trap the end of the spring under the roll pin.
7. The roll pin will likely flex and not want to enter the through hole on the opposite side of the spring tunnel. Gently guide the roll pin into the opposite side through hole with the punch/dowel with one hand while tapping the roll pin into the receiver with the other hand.
8. Tap the roll pin until it is flush with the receiver.
9. Adjust the rear sight per the TM. (remember to put a drop of blue locktite on the allen screw that locks the 2 adjusting wheels together)
