Understanding the Might of the 6.8 SPC
The 6.8mm Remington Special Purpose Cartridge (6.8 SPC) was developed specifically to address perceived shortcomings of the ubiquitous 5.56mm NATO round, particularly regarding its performance against more substantial targets. Designed for the military, the goal was to provide enhanced stopping power while maintaining compatibility with the AR-15 platform.
The 6.8 SPC offers a compelling alternative. It’s important to understand its trajectory. This cartridge typically fires bullets with a diameter of .277 inches, often weighing between a hundred and fifteen grains. This is substantially heavier than the standard fifty-five-grain bullet commonly used in 5.56mm ammunition. The heavier bullet carries significantly more energy downrange. This translates to a greater impact force, allowing the 6.8 SPC to effectively engage targets at distances exceeding what is possible with the five-five-six.
The benefits of the 6.8 SPC are numerous. One of the most significant advantages is its improved terminal ballistics. It can create a larger wound cavity compared to the five-five-six, increasing the chance of incapacitating a threat more quickly. This makes it particularly attractive for self-defense scenarios and hunting applications where quick and decisive stops are paramount.
Furthermore, the 6.8 SPC maintains a relatively flat trajectory over distance, making it a very accurate cartridge. Many hunters favor the 6.8 SPC because it has excellent stopping power. It can down medium-sized game such as deer, pigs, and other similar animals, making it a versatile cartridge.
Of course, no cartridge is perfect. The 6.8 SPC does have certain drawbacks. One of the most significant is the increased cost of ammunition. 6.8 SPC rounds are generally more expensive than the equivalent five-five-six rounds. This factor might influence some shooters, who prefer a more budget-friendly option.
Assembling Your Weapon: Component Choices and Compatibility
Building a **6.8 SPC upper on an AR-15 lower** is a straightforward process, especially if you already have experience building or working on AR-15s. The first, and arguably most critical aspect, is ensuring compatibility. Fortunately, the 6.8 SPC upper receivers are designed to work with standard AR-15 lower receivers. You won’t require any special modifications to the lower receiver.
Let’s delve into the components:
The upper receiver itself serves as the backbone for your build. You can opt for a stripped upper receiver, which allows you to select each component individually, or a complete upper receiver, which offers the convenience of a pre-assembled unit. Stripped uppers give you the freedom to choose parts to suit your specific needs.
A key component is the barrel. The barrel directly influences the accuracy and performance of the rifle. When selecting a 6.8 SPC barrel, you’ll need to choose a length appropriate for your planned use. Shorter barrels are more maneuverable and suited for close-quarters engagements, while longer barrels provide improved ballistic performance and greater range. Look at the twist rate – a faster twist rate can stabilize heavier bullets.
The bolt carrier group (BCG) is crucial for the safe and reliable operation of your rifle. Make sure you get a BCG specifically designed for the 6.8 SPC. This is because the dimensions and tolerances of the 6.8 SPC cartridge differ from the five-five-six. Using the correct BCG ensures reliable cycling and prevents potential malfunctions.
Next, the charging handle is a standard AR-15 component. However, some users opt for an enhanced charging handle, which provides a larger grip and is easier to manipulate, especially when wearing gloves or under stress.
The handguard or forend is another element that can significantly enhance your shooting experience. Consider what accessories you plan to mount. If you plan to attach lights, lasers, or other accessories, ensure that the handguard offers sufficient mounting options, such as M-LOK slots or Picatinny rails. Free-float handguards are popular, as they prevent the handguard from touching the barrel, which can improve accuracy.
The gas system regulates the flow of gas to cycle the action. The gas block and gas tube must match the barrel’s length and, in some cases, your handguard choice. Some shooters prefer adjustable gas blocks that allow fine-tuning of the gas system to optimize performance with different ammunition types or suppressors.
A muzzle device is the final element of the front end. A muzzle brake helps reduce felt recoil. A flash hider minimizes the muzzle flash, which is crucial for low-light situations.
Don’t underestimate the importance of good optics. A quality scope or red dot sight can dramatically improve your accuracy and target acquisition speed.
Putting It Together: The Art of Assembly
Before you begin, gather the essential tools. You’ll need a vise to secure the upper receiver, a barrel wrench to tighten the barrel nut, a torque wrench to ensure proper torque, punches to install the roll pins, and a set of armorers’ tools to aid in the process.
Start by clamping the upper receiver into the vise. Next, install the barrel into the upper receiver. Make sure the barrel extension aligns properly with the receiver. Then, thread the barrel nut onto the receiver. This is where the barrel wrench comes in handy. Tighten the barrel nut to the manufacturer’s specifications, typically using a torque wrench. Proper torque ensures the barrel is firmly secured to the receiver.
Next, install the gas block onto the barrel. Then, install the gas tube. It is important that the gas tube is aligned with the gas key on the bolt carrier group.
Then, install the handguard. If your handguard uses a barrel nut, be sure to torque it to the manufacturer’s specifications.
Finally, install the upper onto your AR-15 lower receiver. Ensure all components are correctly aligned.
After the upper is assembled, you’ll insert the BCG into the upper and test the action to confirm everything functions smoothly.
Ammunition, Range Time, and the Path to Mastery
Selecting the right ammunition will have a profound impact on your shooting experience. There are a variety of 6.8 SPC loads available, with different bullet weights and designs. Some are optimized for hunting, offering superior expansion and penetration. Others are tailored for target shooting, providing excellent accuracy and consistent performance. Experiment with different loads to find the one that best suits your needs.
Assembling your rifle and selecting your ammunition are only part of the equation. Range time is crucial. Start by breaking in the barrel to optimize its performance. Many gun owners follow a barrel break-in procedure, which involves cleaning the barrel after each shot for the first several shots, or following the manufacturer’s instructions.
Next, you will want to zero your optics or sights. The process of zeroing involves adjusting your sights until your shots consistently hit the point of aim. Proper zeroing will ensure that your shots land where you intend them to, whether you are engaging targets at close range or at distance.
Even when shooting carefully, malfunctions can occur. It’s critical to learn how to diagnose and resolve common issues. If the rifle fails to feed, or if the bolt doesn’t fully close, investigate and correct the issue.
Maintaining Your Firearm: Longevity and Reliability
Regular maintenance is crucial for ensuring the longevity and reliability of your rifle. The 6.8 SPC produces significant amounts of carbon buildup. Regularly cleaning the barrel with a quality bore solvent and brush will remove residue. The BCG also requires regular cleaning and lubrication. A clean and well-lubricated BCG is less likely to jam or malfunction. Pay close attention to the moving parts, and lubricate them appropriately.
Proper storage is equally important. Store your firearm in a secure location, away from children and unauthorized individuals. Protect it from the elements, ensuring that it’s kept dry and at a stable temperature.
Finally, inspect your rifle periodically for wear and tear. Replace worn or damaged components promptly. This will prevent potential malfunctions and ensure your rifle functions safely.
The Benefits of Building a 6.8 SPC AR-15
The reasons for building a **6.8 SPC upper on an AR-15 lower** are compelling.
Firstly, it provides a significant upgrade in ballistic performance over a five-five-six chambering.
Secondly, it offers you a solution that can provide more confidence in the field or on the range.
Thirdly, the AR-15 platform, because of its modularity, ensures that you can easily adapt to your needs.
Conclusion: Embracing the Power
Building a **6.8 SPC upper on an AR-15 lower** is a rewarding endeavor. Through understanding the cartridge, selecting compatible components, assembling the upper receiver correctly, and practicing safe gun handling, you can create a powerful and versatile firearm. This combination of performance and adaptability can make your AR-15 capable of handling a wide variety of tasks.
This guide provides a comprehensive overview of the process. Embrace the journey, refine your skills, and enjoy the power and versatility of the 6.8 SPC.
