My M16A1 was approved this week, and hope to receive stamp any day to bring her home. I have purchased all new Colt lower parts and a Geissele SSF trigger to install.

This is my first M16, so my question is what do I need to know about swapping the fire control group and sear parts? It looks pretty straight forward but wanted to make sure I do it right.

1. Does the fire control group need to go in before the sear?
2. Does the sear pin only go in one way?
3. Should the sear be installed before the safety?
4. Anything else I need to know?

Thanks in advance!

1. No, you can remove the FCG without removing the sear.
2. The GI sear pins are ambi, but the sear spring's retention leg is on the right. If you go in from the left side of the receiver, the pin only has to insert to the retention groove, instead of bumping past the first groove to fully insert and get to the second groove when coming in from the right. Sometimes it's easier to get the pin started coming in from the right, though.
3. No, the sear leg can swing enough out of the way to allow insertion or removal of the safety.
4. not sure - I never used a Geissele in my autos so don't know if they need special pins or anything. The size of the end of your firing pin is correct to use it as a sear pin punch.

ETA: 1. might not apply to your Geissele SSF. All the above is correct for GI FCG and sear, though.

Thank you