
A while back, I posted the Geissele trigger install video while building the AR-MPR AR-15 rifle. I liked the Geissele trigger used on the AR-MPR project so much, that I decided to buy one for the AR-308 project – this time a different version. In this video, we’ll remove the factory trigger, and replace it with the Geissele Super Dynamic SD-C trigger assembly.
Here’s a picture that shows the parts and tools used:

Tools and Trigger Components used for the Geissele SD-C trigger install - Image Copyright 2011 Ultimate Reloader
In the picture above, we have (from left):
- 1/8″ punch
- Trigger pin alignment and install tool
- Top: Hammer assembly Bottom: Trigger and disconnector
- Grease
- Top: Product booklet Bottom: Product bag
If you are familiar with the process, it’s easy, and you can do this upgrade in about 10 minutes. If you watch the video and then try it your self for the first time, plan on 15 – 20 minutes total. Don’t forget to put a drop of oil on the pins and some grease on the sear engagement surfaces!
Results: If you recall from the Rifle Overview Video, the stock trigger had a 7.5lb pull. Following the upgrade, we have a crisp and smooth 5lb pull with minimal pull distance. It works great!



In this, the final AR-15 assembly video, we’ll walk through the installation of the takedown pin and the buttstock assembly. Finally, we’ll put the upper and lower together for the first time and establish basic functionality (formal function check to follow in subsequent posts).



