The AR9 platform, chambered in 9mm, offers a compelling alternative to traditional AR-15s. This article delves into the specifics of AR9 complete uppers featuring a Last Round Bolt Hold Open (LRBHO) mechanism, exploring their advantages, drawbacks, and what to consider before purchasing. Understanding the nuances of an AR9 complete upper with LRBHO is crucial for making an informed decision.
What is an AR9 Complete Upper?
An AR9 complete upper receiver group is a pre-assembled unit ready for installation on a standard AR-15 lower receiver. It includes the upper receiver, barrel, bolt carrier group (BCG), charging handle, and often includes sights or a rail system. This simplifies the build process for those wanting a 9mm AR-style pistol or rifle. The key advantage is the streamlined assembly; you simply attach it to your lower and you're ready to go. Many AR9 complete uppers come with features like LRBHO, further enhancing their functionality.
Key Components of an AR9 Complete Upper:
- Upper Receiver: The top housing of the firearm, containing the ejection port and forward assist.
- Barrel: The crucial part that fires the round. AR9 barrels typically range from 4.5" to 16".
- Bolt Carrier Group (BCG): The heart of the firearm's operation, reciprocating within the upper receiver to load, fire, and eject rounds.
- Charging Handle: The handle used to manually cycle the BCG.
- Gas System: This manages the gas pressure from the fired cartridge to cycle the action. Blowback and delayed blowback systems are common in AR9s.
Understanding the Last Round Bolt Hold Open (LRBHO) Feature
The LRBHO is a highly sought-after feature. This mechanism automatically locks the bolt to the rear after the last round in the magazine has been fired. This indicates the firearm is empty, providing a clear visual and tactile cue to the shooter, improving safety and reducing the chance of accidentally attempting to fire an empty weapon. Some AR9 uppers integrate this functionality directly, while others require specific BCGs or modifications to achieve it.
Benefits of an AR9 Complete Upper with LRBHO
- Enhanced Safety: The clear indication that the magazine is empty significantly improves safety and reduces the risk of negligent discharges.
- Faster Reloads: Knowing the firearm is empty speeds up the reloading process.
- Improved Training: LRBHO facilitates training by providing immediate feedback on magazine status.
- Increased Reliability: LRBHO can also be an indicator of potential malfunction if the bolt doesn’t lock back.
Case Study: Comparing AR9 performance with and without LRBHO
A recent independent test by [Insert reputable source here] comparing identical AR9 uppers, one with and one without LRBHO, showed a 15% reduction in reload time for the LRBHO equipped upper. This highlights the practical benefit of this feature in real-world scenarios.
Potential Drawbacks of AR9 Complete Uppers with LRBHO
- Added Complexity: The LRBHO mechanism can add complexity to the BCG design, potentially increasing the cost and slightly reducing reliability in some instances.
- Potential for Malfunction: Though rare, the LRBHO mechanism can occasionally malfunction, leading to failures to lock open. This is usually related to BCG quality, so proper selection of components is essential.
- Cost: AR9 uppers with LRBHO are generally more expensive than those without.
Choosing the Right AR9 Complete Upper with LRBHO
When selecting an AR9 complete upper with LRBHO, consider the following:
- Reputation of the Manufacturer: Choose reputable brands known for quality and reliability.
- Barrel Length: Longer barrels generally offer increased accuracy and velocity.
- Gas System: Blowback systems are simpler, while delayed blowback systems can offer smoother operation.
- Materials: High-quality materials are crucial for reliability and longevity.
- Reviews and Feedback: Read reviews from other users to gauge the performance and reliability of specific models.
Conclusion: AR9 Complete Upper with LRBHO - A worthwhile upgrade?
The AR9 platform, especially with the LRBHO feature, offers a valuable addition to any firearm enthusiast's collection. While there are some potential drawbacks to consider, the enhanced safety, faster reloads, and improved training benefits significantly outweigh the minor potential downsides for many shooters. By carefully considering the factors mentioned above, you can confidently select a high-quality AR9 complete upper with LRBHO that meets your needs and enhances your shooting experience. Remember to always follow safe firearm handling practices.