The .45-70 Government cartridge, a venerable round with a rich history, continues to attract enthusiasts for its power and accuracy. Building a custom AR-15 platform chambered in this powerful caliber requires careful consideration, and the upper receiver is a crucial component. This guide explores the key aspects of choosing a 45-70 AR upper receiver, focusing on compatibility, construction, and performance.
Understanding the Challenges of a .45-70 AR Upper
Before diving into specific upper receivers, it's important to understand the unique challenges presented by the .45-70 cartridge. Its significantly larger diameter and heavier recoil compared to standard AR-15 calibers necessitate robust construction and specialized components. A standard AR-15 upper will not accommodate a .45-70 round.
Key Differences from Standard AR-15 Uppers:
- Larger Bolt and Barrel: The .45-70 requires a substantially larger bolt and barrel to handle the cartridge's dimensions and pressures.
- Enhanced Strength: The upper receiver must be reinforced to withstand the increased recoil and stress. This often means heavier materials and potentially different manufacturing processes.
- Specialized Ejection: The larger cartridge demands a modified ejection system to ensure reliable cycling.
- Magazines: Expect specialized magazines designed specifically for the .45-70 round, often with limited capacity.
Choosing the Right 45-70 Upper Receiver: Key Considerations
Selecting the right 45-70 upper receiver involves careful evaluation of several factors:
1. Material and Construction:
- Material: Look for uppers crafted from high-quality materials like hardened steel or billet aluminum. The robustness of the material directly impacts the receiver's ability to withstand the .45-70's powerful recoil.
- Manufacturing Process: Consider the manufacturing process employed. Forged or billet uppers generally offer superior strength and durability compared to cast options.
2. Compatibility:
- Lower Receiver: Ensure the upper receiver is compatible with your chosen lower receiver. This may require a lower receiver specifically designed or modified for the .45-70 platform. Pay close attention to any specifications provided by the manufacturer.
- Bolt Carrier Group: The upper must be compatible with the appropriate .45-70 bolt carrier group (BCG). This is a critical component for reliable functioning and should be chosen from a reputable manufacturer.
3. Barrel Length and Profile:
- Barrel Length: The optimal barrel length for a .45-70 AR upper depends on intended use. Longer barrels can improve accuracy and velocity, while shorter barrels offer greater maneuverability. Consider the balance between accuracy and portability.
- Barrel Profile: Different barrel profiles affect weight, heat dissipation, and accuracy. Heavy profiles offer better accuracy and reduced recoil, while lighter profiles enhance maneuverability but may exhibit more recoil.
4. Manufacturer Reputation:
Choose reputable manufacturers with a proven track record of producing high-quality, reliable firearm components. Check online reviews and forums to gauge the reputation of potential suppliers. Avoid purchasing from unknown or unreliable sources.
Beyond the Upper: Completing Your .45-70 AR Build
The upper receiver is just one part of a successful .45-70 AR build. Remember that you'll need other specialized components, including a compatible lower receiver, bolt carrier group, magazines, and ammunition. Thorough research and careful selection of each component are crucial for a reliable and safe firearm.
Conclusion: Embracing the Power of the .45-70
Building a .45-70 AR-15 platform is a rewarding experience, but it requires meticulous planning and careful component selection. By focusing on the key considerations discussed in this guide, you can confidently choose the right 45-70 government upper receiver and create a powerful and reliable rifle tailored to your needs. Remember always to prioritize safety and consult with experienced firearm professionals if you have any questions or concerns.
