How to Install a Dust Cover on the Blackout Defense Mark 2 Upper Receiver

If you just purchased a Blackout Defense Mark 2 Upper Receivers for your build, congratulations! You have made an excellent investment in a high-quality billet upper made from the best aerospace-grade aluminum and protected by a hard coat black anodize finish.

We’ll discuss here how to install the dust cover (also known as the ejection port cover) of your choice.

Typically, the first step to installing your dust cover would be to install the c-clip onto the dust cover rod. The c-clip is designed to secure the rod to the upper receiver, but it is a small part that is hard to hold and easy to use. The Blackout Defense upper receiver eliminates the need for a c-clip. We designed the upper so that the dust cover rod is supported and protected by the barrel nut and handguard itself.

With the elimination of the c-clip, the steps to install a dust cover onto the Blackout Defense upper are as follows:

  1. Lightly oil the dust cover rod and feed the smooth end through the upper receiver and first half of the cover.
  1. Push the dust cover spring so that both tails point up. While holding the side with the short tail, rotate the side with the long tail down and continue feeding the dust cover rod through the entirety of the spring and the other half of the cover.
  1. Hold the dust cover in the closed position and use a rubber mallet to tap the dust cover until it locks closed. Open the dust cover and repeat this 2-3 times. This action will cause the dust cover locking ball to punch through the excess material (left there by design) on the locking area of the upper.
  1. Check for proper functionality.

Step 3 is unique to the Blackout Defense upper receiver. We designed the upper receiver to leave about .0005” excess material in the locking area of the upper. When the dust cover is initially tapped closed with a rubber mallet, the dust cover locking ball will punch out its own path/groove into that excess upper material. This ensures a perfect, consistent, and repeatable lock that is unique to the dust cover of your choosing.

If you have any questions, do not hesitate to reach out to us by email or phone:


Phone: 480-781-0573.