With the scope mounted the gun was fully assembled and ready to fire. I had purchased the lower parts kit without a trigger because I knew I would be adding a much better unit than the USGI work-alike that would come in the kit. During assembly I used an old stock trigger I had on hand. This trigger has been used to fire well over 10k rounds and had been treated to the “10-minute trigger job”. Even so it when I dry fired it I was not too happy so I decided to wait on live fire until I could get a more appropriate trigger installed. I had heard very good things about Geiselle’s Super Semi-Auto trigger and I figured it would be ideal for this project.
The Geissele (rhymes with “wisely”) folks really know what they are doing. They provide triggers to US armed forces. The Super Semi-Auto (SSA) is based on their full-auto M16 trigger. It has no adjustments and all springs are captive. If you read my post on installing the Apex Tactical action kit in my M&P9 you will understand my aversion to having springs fly around the room. What sets these triggers apart is that all the bearing surfaces are cut by “wire EDM” (see how it works here) which makes incredibly precise cuts with no tooling marks. This makes for a very smooth surface with edges that are measured in microns.
I specifically chose the SSA-E (enhanced) model which is a lighter version of the SSA trigger. This trigger is widely available and can be had for around $230. Along with the captive springs, a nice feature is that they include a slave pin to assist with the trigger installation. Place the slave pin in the trigger group to hold the disconnector in place while the assembly goes down into the receiver. Once in place the trigger pin is easily pushed through from outside the receiver to displace the slave pin. Both hammer and trigger are held in place by spring legs just like normal AR-15 FCG parts. This is certainly easier than the Timney system which requires set screws and extra fiddling.
For a carbine I would probably stick with the SSA because the bit of extra trigger weight would be desirable. For my precision gun I felt that less is more. The first stage is a very linear 2.3 lbs. that is easily prepped when you are ready to shoot while the second stage is a 1.2 lb. “snap” just like you would want. Geissele uses the term “candy cane” but “glass rod” would also apply. For long-range shooting I can’t imagine a better setup.
The trigger went in without issue in 10 minutes and with that the rifle was truly ready for the range! Part V is the final post in this series. In it I will cover the overall experience of shooting the rifle.