I continue to build out a Rock River Operator given to me as a gift with components I’m adding as my budget allows. A big step in the process was adding the Geissele Hi-Speed National Match Trigger #05-127. It is designed for NRA High Power Rifle competition with highly modified AR-15-type rifles. Geissele’s directions are refreshingly clear and honest about the installation. “The Geissele Automatics National Match/Designated Marksman Rifle (DMR) Trigger will lighten the trigger pull relative to a standard trigger. This lightened trigger pull will make the weapon easier to discharge. You must recognize and accept this fact before installing this National Match trigger. If you do not want a lighter than standard trigger pull, or are not willing to accept responsibility for your weapon’s safety, the safety of yourself, and the safety of those around you, do not install this trigger. Geissele Automatics recommends installation by a certified gunsmith only.” In the self-sealing clear-plastic package are an installation tool, grease, oil, Allen wrenches, trigger and the hammer, and two dedicated pins that are used once everything else is installed and adjusted. Three trigger springs came with the unit: one for Service Rifle (total pull weight 4.5+ pounds), one for Designated Marksman Rifle (total pull weight 4 pounds), and the Match, the lightest of the three (2.5 pounds total weight), which I installed.
I will say right off that I chose the wrong spring weight, and that’s not Geissele’s fault. The RRA trigger ran about 4 pounds of let-off weight in its single-stage mode, and the gun delivered 2.5-inch groups with most ammo at 100 yards. Some of that was the gun—some was me. As I broke shots, my concentration would pull off the sight picture to feeling the trigger, which was heavier than I wanted. Also, I prefer two-stage triggers in my bolt guns, and I wanted the same in the Operator. The National Match Trigger certainly promised that kind of performance.
Installing the Match spring and trigger took me several hours because I was unfamiliar with its requirements. I won’t go into the detailed assembly process here, but if you’re considering buying this trigger, I suggest you first download the instructions and see if you want to tackle the job. The instructions for the NMT are here. There is also a series of Geissele installation videos here. Or you can find them by searching for “Geissele Automatics” on YouTube.
The videos were a big help. Before you get started, I’d recommend watching the video, “Choosing the Right Trigger for You.” If you decide on the Geissele NMT, there are videos that explain the installation in superb detail, and so does the instruction sheet that comes with the trigger. The first NMT installation video appears in the window below.
[youtube http://youtu.be/X810NhGBxCw nolink] I want to give you the benefit of my mistakes and suggest for most AR-15s, the NMT set with the Match spring is simply too good. In my RRA Operator, the first stage required only 1 pound 5 ounces of pressure to move. The second stage broke at 2 pounds 3 ounces.
Also, consider whether you have the time and patience to work the trigger to perfection. I learned a lot installing the trigger, but I might have been just as happy to have taken it to a gunsmith with instructions on what I wanted—or Geissele will do the installation for you.
The NMT with Match spring is a fantastic trigger, and for match or bench use, I’d probably leave it as it is. My bench-accuracy results at 50 yards are super. But now I want this trigger to be a little less sensitive, so I plan to install the DMR spring next and see if I can keep the sweet let-off, but not have to be so careful with it. If I had it to do all over again, I’d start with the Service Rifle spring and move down from there.