DIY AR-15 Build: Trigger Guard Installation

by July 14, 2011 07/14/11
DIY AR-15 Build: Trigger Guard Installation
7 of 8 in the series DIY AR-15 Build

Today in part seven of our DIY AR-15 Build you’ll learn how to install a Magpul MOE Trigger Guard into your Lower Receiver.

While installing a trigger guard might not seem to be a very complicated step that warrants it’s own article, there are a few tricks that can help you from making a fatal mistake when assembling your lower.

The ears (pin extensions) that hold the trigger guard roll pin are more fragile than you might think and if care is not taken with this step to find an appropriate multi-level surface, you could potentially wind up breaking one of these off.

If that happens, you might not only be out a lower receiver, but also a $200 tax stamp if you’ve put in to SBR your lower before assembling it. We hope this article will shed a little light on the installation and prevent any catastrophes from happening while you’re assembling your trigger guard.

Continue reading for our step-by-step instructions for installing the Trigger Guard with detailed photos and video.

Trigger Guard Installation

For this step, you won’t be using the trigger guard that’s included with the Stag Arms Lower Parts Kit we recommend, unless you’d like to. The benefit the Magpul MOE Polymer Trigger Guard has over stock trigger guards is the contour and removal of any hard edges that will eventually dig into your fingers after a long day of shooting.

The Magpul Trigger Guards also remove that annoying gap you might have seen at the rear of a standard trigger guard. Not having the gap makes for a more natural roll as you hold the pistol grip. The “V” shape of the MOE also helps finger placement when wearing gloves, as it allows for some extra room.

DIY AR-15 Build: Trigger Guard Installation

As noted above, a multi-level surface is what’s truly important about this step to ensure disaster doesn’t strike. There are a few options for this, in the video you’ll see that we were able to use the Magpul MOE Stock and the Lower Receiver Vise Block to create this. Alternatively you can also use the Brownell’s Front Sight Bench Block in addition to the Rifle Bench Block. If you already have these blocks, it’s definitely a good way to go, but you don’t need to go out an purchase them just for this step.

You can always create your own multi-level surface out of wood if you want to spend the time. It’s beneficial to create one out of wood if you plan on building many rifles, as it will save you time and headache in the future. The good thing about the Brownell’s blocks though is that they do double duty.

Parts Needed

DIY AR-15 Build: Trigger Guard Installation

Tools Needed

Assembly Instructions

  1. Rest your Lower Receiver on the Front Sight Bench Block according to the photo, using it in this fashion will give you the support you need so that you don’t accidentally break off one of the Roll Pin ears on your lower when tapping in the Roll Pin.
  2. Place the Trigger Guard with the large hole aft; using the #4 Holder, start to tap in the included Roll Pin. Finish tapping the roll pin flush (on both sides) with the #4 Roll Pin Punch. This can also be done without the aforementioned punches, but they do make it easier and prevent misalignment of roll pins.
  3. Finish installing the Trigger Guard by screwing down the front set screw until flush, using a 1/16″ Hex Key.

Join us back here soon for our 8th installment in the DIY AR-15 Build where we’ll be assembling the Buttstock before moving on to the Upper Receiver!

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Ken Stroede
Ken Stroede

Any tips on removing the trigger gaurd without damaging anything?


Brain, I have assembled dozens of AR with many differnt brands of receivers and parts kits and have never had one work out. The roll pins fit very snug in the gaurd and receiver ears.


couldnt you use a C clamp to press the pin in instead of tapping it in and risking the damage? pretty sure thats what i did to repair a friends AR.


I would like to pass on a few things I have found very helpful to installing the trigger guard pin. The first thing I like to do is to bevel the leading edge of the roll pin with a polishing stone or needle file. The other important thing I like to do is to lube the pin with your favorite gun oil or grease. As this helps lessen the friction between the pin, receiver and trigger guard itself. You can also polish the whole pin before installing it, But I find that is really not needed. I have assembled many ar's over the years using these technics along with the steps you show above. As always be safe.

Eric S.
Eric S.

I run a MOE and when I installed it I didn't think of damaging the ears. Good article as it would really suck to destroy your lower doing a "simple" task.

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