Building an AR-15 platform rifle chambered in 7.62x39mm offers a unique blend of familiarity and exciting new challenges. While the basic AR-15 design remains the same, converting to this popular Eastern Bloc cartridge necessitates careful consideration of several key components. This guide provides a detailed overview of the process, helping you build a reliable and accurate 7.62x39 AR-15.
Understanding the 7.62x39 Cartridge and its Implications
The 7.62x39mm cartridge, widely used in the AK-47 and its variants, presents distinct characteristics compared to the standard 5.56 NATO round. Its larger diameter and heavier bullet necessitate modifications to the AR-15 platform to ensure safe and reliable operation. Key differences include:
- Case Diameter: The 7.62x39mm cartridge has a significantly larger case diameter than the 5.56 NATO round. This requires a different bolt face and potentially a modified bolt carrier group.
- Headspace: Accurate headspace is crucial for safe and reliable function. Incorrect headspace can lead to malfunctions and potentially dangerous situations.
- Magazine Compatibility: Standard AR-15 magazines are incompatible with 7.62x39mm cartridges. You'll need magazines specifically designed for this caliber.
- Recoil: Expect significantly more recoil compared to a 5.56 NATO AR-15.
Essential Components for Your 7.62x39 AR Build
Building a 7.62x39 AR requires specific components designed for this cartridge. Cutting corners here can lead to malfunctions and potentially dangerous consequences. Essential parts include:
1. Upper Receiver:
While a standard AR-15 upper receiver might work, using a purpose-built 7.62x39 upper receiver is strongly recommended. These uppers are specifically designed to handle the increased pressures and dimensions of the cartridge.
2. Bolt Carrier Group (BCG):
A 7.62x39mm BCG is absolutely essential. Standard 5.56 BCGs are not compatible and attempting to use them will likely result in catastrophic failure. The BCG must be designed for the larger diameter of the 7.62x39 cartridge and the increased pressures generated.
3. Barrel:
Choosing the right barrel is crucial for accuracy and reliability. 7.62x39 barrels come in various lengths and profiles, each impacting accuracy and handling characteristics. Consider your intended use and preferences when selecting a barrel. Chrome-lined barrels are generally preferred for longevity and durability.
4. Magazine:
You'll need magazines specifically designed for 7.62x39mm. Several reputable manufacturers produce reliable magazines for this caliber. Research different options and choose magazines with a proven track record of reliability.
5. Gas System:
The gas system plays a vital role in the reliability of your 7.62x39 AR. Proper gas port sizing and a well-tuned gas system are key to reliable cycling. Consider adjustable gas blocks for fine-tuning the system to different ammunition loads.
6. Buffer System:
The increased recoil of the 7.62x39mm round often necessitates a heavier buffer system compared to a standard 5.56 NATO AR-15. This helps to manage recoil and improve reliability.
Building Your 7.62x39 AR: A Step-by-Step Guide
The actual assembly process mirrors that of a standard AR-15 build, with the exception of using the specific 7.62x39 components described above. Thorough familiarity with AR-15 assembly is highly recommended before attempting this build. Many detailed resources are available online and through reputable firearm publications that thoroughly cover this process. Consult these before commencing your build.
Safety Considerations
Building any firearm requires attention to safety. Always follow safe gun handling practices and consult with experienced gunsmiths or professionals if you are unsure about any step in the process. Improper assembly can lead to malfunctions, damage to the firearm, and potentially serious injury.
Conclusion: Enjoy the Build, But Prioritize Safety
Building a 7.62x39 AR-15 offers a rewarding experience for experienced builders. However, this project requires careful planning and attention to detail, especially concerning the specific components needed for safe and reliable function. Prioritize safety throughout the entire process, and remember that responsible gun ownership extends to safe and informed building practices.
