Run and Gun AR-15 Lower Build

Run and Gun AR-15 Lower Build

FTC Disclosure: Some of the items reviewed in this article were provided at no charge.

If you’ve been following us for a while now, you know that we’ve been working on a series of articles focused on assembling a purpose-built AR-15.

Yeah, we know, everyone and their brother has done AR-15 build articles and videos. Many of those articles and videos have been produced by people building their first AR. We also know that you expect more from us than to simply follow the crowd of other evil black rifle builders. Fortunately, because we know that you expect more from us, we intend to provide something a little different in this series of articles.

This is the third and final article in our series covering the build of our “Run and Gun” AR-15. In this article we cover our run and gun AR-15 lower build. If you would like to read the first article in the series, click here. To read the second article, click here.

As Yogi Berra (may he rest in peace) used to say, assembling an AR-15 lower isn’t “rocket surgery.” OK, maybe he never said that about building AR-15’s but we like the rocket surgery part.

In our first article, we reviewed the components of our build as well as some of the tools that make the assembly much easier. One of those tools is a lower receiver vise block (pictured below). The vise block helps protect the lower receiver from damage and provides a solid work space for your assembly.

Vise Block
Vise Block

Place the lower receiver on the vise block and install the magazine catch/release assembly. We used a pencil eraser (see photo below) to press the release button into the receiver while threading in the catch lever. The eraser won’t scuff or damage the button while providing a “stop” for the lever as it is threaded into the button.

Pencil Eraser to Assist with Magazine Catch Install
Pencil Eraser to Assist with Magazine Catch Install

Improper installation of the trigger guard can result in a broken rear guard tab. Be sure to support the tabs when driving the pin into the rear tabs.

We used the vise block as a support.

Use the Vise Block to Support the Trigger Guard Tabs
Use the Vise Block to Support the Trigger Guard Tabs

Next, install the bolt catch lever.

We used an awl with a plastic handle to hold the lever in place while we started the roll pin (see photo below). The plastic handle won’t mar the finish of the receiver.

Holding the Bolt Catch Lever in Place
Holding the Bolt Catch Lever in Place

Use a roll pin starter punch to start the pin (see photo below). Allow the roll pin to push the awl out of the receiver as you drive the pin through the lever. Use a roll pin finisher punch to complete the assembly. This method saves you the time associate with putting tape all over your receiver to protect it from scuffs or nicks during the process.

Roll Pin Punch
Roll Pin Punch

One of the tricks that we use when installing the front take-down pin is to rotate the vise block 90° in the vise so that the opening for the take-down pin spring is facing up (see photo below).

Rotate the Block in the Vise
Rotate the Block in the Vise

Drop the spring into the opening (see photo below) and carefully insert the detent pin. Use a razor blade to hold the spring and detent pin in place as you slide the take-down pin through the tabs on the front of the receiver.

Detent Spring in Vertical Opening
Detent Spring in Vertical Opening

The RISE Armament trigger is a simple drop-in installation. No external springs to mess with.

RISE Armament Trigger
RISE Armament Trigger

When installing the fire selector switch and hand grip, flip the receiver upside-down on the vise block. Drop the detent pin into the opening (see photo below).

Fire Selector Detent Pin
Fire Selector Detent Pin

Place the spring in the hand grip and utilize a long screw driver or Allen wrench to tighten the screw.

A Long Allen Wrench Helps with the Hand Grip Installation
A Long Allen Wrench Helps with the Hand Grip Installation

Install the buffer tube and rear take-down pin. Use a razor blade, again, to hold the take-down pin’s detent pin and spring in place while threading the buffer tube into the receiver. Be sure to put a little grease on the threads of the receiver and some anti-seize on the face of the receiver where it contacts the stock tube.

Be Careful with the Rear Take-down Pin's Detent Spring
Be Careful with the Rear Take-down Pin’s Detent Spring

Finally, insert the buffer and spring into the buffer tube. Depending on your stock, you may still have to install the actual butt stock. Our Ace Ultra-light needed no additional installation other than tightening the clamp screw.

Ace Ultra-light Clamp Screw
Ace Ultra-light Clamp Screw
Install the Buffer and Spring.
Install the Buffer and Spring.

And … the proof is in the pudding (or the ‘putting’ of rounds down range). Here’s a typical 4″ target at 100 yards with Hornady 55 grain practice ammo.

Typical 100 Yard Target
Typical 100 Yard Target