How to Build an AR

If you want to build an AR, you need the right components, the right tools, and the knowledge to build it right. We will cover all of these elements in this series of instructions. We include instructions for all three AR classes, including the AR-15 (small frame AR), AR-10 (large frame AR), and AR-9 (pistol caliber AR). While we prefer to build on the Aero Precision Enhanced platforms, we also include instructions for the standard AR platform.

PB Tips Whichever manufacturer and platform you use, we strongly recommend that you verify that the upper receiver and lower receiver mate properly before you begin. Place the upper receiver on the lower receiver and verify that the pivot and takedown channels are clear from one side to the other. Better, insert both the pivot and takedown pins into the applicable holes. If you cannot see through, unobstructed, or if you cannot feed the pins through at the same time, STOP. You may have a problem with your receivers. We only suggest this because we have run into this issue before, with a brand that we no longer use and will never use again.

Upper Receiver Assembly

In this set of instructions, we will guide you, step by step, through the process of assembling your upper receiver.

We will approach this in the most pragmatic way that we can and in a specific sequence to avoid issues in subsequent steps.

We cover all three classes of AR in this series (AR-9, AR-15, and AR-10).

Lower Receiver Assembly

In this set of instructions, we will guide you, step by step, through the process of assembling your lower receiver.

As with the upper receiver, we will cover the steps in a specific sequence to avoid issues in subsequent steps.

We cover all three classes of AR in this series (AR-9, AR-15, and AR-10).

Final Assembly

The final step to build an AR should be the easiest of the three efforts. If you have built correctly, on a quality platform, with quality components, you should be able to slap the upper and lower together and do a quick function check. However, you may face a couple of issues that we will walk you through.

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