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How Many Rounds Can You Fire from an AR-15 Before Failure?

This article seeks to examine the resilience and operational limits of the AR-15 when subjected to the rigors of sustained full-auto fire, pushing the firearm well beyond its standard usage parameters.

The dynamic nature of the real world means that individual experiences may vary, and unforeseen factors could influence the performance and durability of a firearm under similar stress conditions. The instances documented here are specific observations from these experiments, providing valuable insights but not universal predictions.

We simply used the observations from these credible video tests to come up with a general idea of how an AR-15 may perform under such conditions as these: Shooting on full auto in rapid succession with an AR-15.

Under sustained full-auto fire, an AR-15 can fail at around 830 rounds with aluminum handguards due to gas tube explosion, and around 480 rounds with plastic handguards due to catching fire and destroying the gas tube. These tests highlight the AR-15’s limitations when used beyond its intended purpose.

Test Results

The test results show a detailed account of the AR-15’s performance under the extreme conditions of sustained full-auto fire, focusing on two primary configurations: one with standard plastic/polymer handguards and another with aluminum free-floating handguards. Each configuration was tested to identify how different materials influence the rifle’s ability to handle and dissipate heat, as well as the overall impact on the firearm’s functionality and structural integrity.

Test 1: Aluminum Free-Floating Handguards

  • Initial Observations: Upon beginning the full-auto fire test, the aluminum free-floating handguards allowed for better initial heat dissipation compared to the polymer counterparts. However, after approximately 210 rounds, the handguards became uncomfortably hot to the touch, indicating a rapid accumulation of heat.
  • Mid-Test Conditions: By the time the count reached around 700 rounds, significant heat buildup was observed. The barrel began to visibly glow red in some spots, a clear indication of extreme overheating.
  • Point of Failure: The test reached a critical juncture at approximately 830 rounds. At this stage, the heat had caused the gas tube to glow visibly and ultimately fail, resulting in an explosion that rendered the rifle inoperable. Additionally, the muzzle device was forcibly dislodged from the barrel due to the pressure and heat. This catastrophic failure highlighted the limits of the rifle’s components when subjected to such extreme conditions.

Test 2: Standard Plastic/Polymer Handguards

  • Initial Heating: Similar to the aluminum handguards, the polymer handguards initially coped with the heat generated by sustained fire. However, extreme heat was already being noticed in the form of smoke after just 150 rounds.
  • Excessive Overheating: By the 300-round mark, the handguards became too hot to handle safely.
  • Catastrophic Failure: The decisive failure occurred after 480 rounds, when the intense heat caused the polymer handguards to catch fire. This not only posed a direct safety hazard but also compromised the structural integrity of the handguards, as well as the gas tube, leading to the rifle becoming inoperable.


The tests illustrate the AR-15’s limitations under the stress of sustained full-auto fire. The aluminum free-floating handguards, while initially providing superior heat dissipation, ultimately succumbed to the intense heat generated by continuous firing. This led to a catastrophic failure of critical components, notably the gas tube and muzzle device. In contrast, the standard plastic/polymer handguards demonstrated a lower threshold for heat resistance, deforming and igniting under less extreme of a round count.

These outcomes underscore the importance of material choice in the design and customization of firearms intended for high rates of fire. While aluminum handguards offer improved heat dissipation initially, their capacity to safely manage the heat generated by sustained full-auto fire is limited. On the other hand, polymer handguards, despite their advantages in terms of weight and insulation, are ill-suited to handle the extreme heat without risking deformation or fire.

The failure points observed in these tests—ranging from overheating to mechanical breakdowns—highlight the inherent risks associated with pushing the AR-15 beyond its design specifications. The results also point to potential areas for improvement in materials technology and design engineering to enhance the rifle’s performance and safety under such demanding conditions.


The tests demonstrated the critical role of material choice in the firearm’s ability to handle extreme conditions and pointed to areas where further research and development could enhance safety and performance. Ultimately, it is important to carefully consider all factors, including material selection, when designing and customizing a firearm for high rates of fire. As technology continues to advance, we can expect to see improvements in materials and designs that will ultimately lead to even more reliable and durable firearms. However, it is also crucial for gun owners and enthusiasts to educate themselves on the limitations of their firearms and properly maintain them to ensure safe and effective operation.

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