Smyth Busters: Are Polymer AR-15 Lowers Any Good?

Published on July 26, 2022
Duration: 3:58

This video from Brownells, Inc. features Steve and Caleb discussing the viability of polymer AR-15 lower receivers. They debunk the myth that all polymer lowers are inferior, explaining that early designs had issues but modern technology has significantly improved. The discussion highlights key stress points, successful designs like the KE Arms KP-15, and the influence of companies like Glock and Magpul in advancing polymer firearm components. The primary benefits discussed are weight reduction and cost-effectiveness, concluding that reputable polymer lowers are a practical option.

Quick Summary

Modern polymer AR-15 lower receivers, unlike early iterations, are a viable and often advantageous option. They offer significant weight reduction and corrosion resistance, with companies like KE Arms implementing reinforced designs to overcome common failure points such as the buffer tube tower. The evolution of polymer technology, influenced by brands like Glock and Magpul, proves their reliability when chosen from reputable manufacturers.

Chapters

  1. 00:00Introduction to the Polymer Lower Myth
  2. 01:13Failure Points and Design Flaws
  3. 01:50Successful Polymer Designs
  4. 02:28The Influence of Glock and Magpul
  5. 03:21Benefits and Conclusion

Frequently Asked Questions

Are polymer AR-15 lower receivers reliable?

Yes, modern polymer AR-15 lower receivers from reputable manufacturers like KE Arms have evolved significantly and are reliable. Early designs had issues, but advancements in material science and engineering have addressed common failure points, making them a viable option for many builds.

What are the main advantages of polymer AR-15 lowers?

The primary advantages of polymer AR-15 lower receivers are significant weight reduction, making them ideal for lightweight builds, and increased corrosion resistance. They can also be more cost-effective to produce, potentially lowering the overall firearm cost.

What is the most common failure point on polymer AR-15 lowers?

The most common failure point identified on less robust polymer AR-15 lower receivers is the buffer tube tower/ring area. This is where the force of the bolt slamming back exerts significant pressure, requiring careful reinforcement in the design.

Which companies are noted for producing good polymer AR-15 lowers?

KE Arms is specifically highlighted for its successful approach to polymer AR-15 lower receivers, particularly their KP-15 monolithic design which reinforces traditional weak points. The influence of companies like Glock and Magpul in advancing polymer technology for firearms is also mentioned.

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