6.8 SPC vs .308: A Comprehensive Cartridge Comparison

The world of ammunition can be complex, with numerous cartridges designed for various purposes. Two popular options often debated are the 6.8 SPC (Special Purpose Cartridge) and the .308 Winchester. Understanding the nuances of each cartridge is crucial for selecting the right one for your specific needs, whether it’s hunting, target shooting, or tactical applications. This article provides a detailed 6.8 SPC vs .308 comparison, covering their history, ballistics, performance, and applications.

A Brief History

6.8 SPC: The 6.8 SPC cartridge was developed in the early 2000s as a potential upgrade for the 5.56x45mm NATO round used in the M4 carbine. It aimed to provide greater stopping power in close to medium-range engagements. It was designed by Remington, along with members of the U.S. Army Marksmanship Unit and U.S. Special Operations Command.

.308 Winchester: The .308 Winchester, also known as 7.62x51mm NATO, was introduced in 1952 as a civilian cartridge based on the 7.62x51mm NATO military round. It quickly gained popularity for its accuracy, range, and effectiveness in both hunting and military applications. It’s a widely used and respected cartridge with a long history of success.

Cartridge Specifications

Understanding the physical characteristics of each cartridge is essential for comparing their performance. Here’s a breakdown of key specifications:

• 6.8 SPC:
  • Bullet Diameter: .277 inches
  • Neck Diameter: .308 inches
  • Base Diameter: .422 inches
  • Case Length: 1.688 inches
  • Overall Length: 2.260 inches
• .308 Winchester:
  • Bullet Diameter: .308 inches
  • Neck Diameter: .343 inches
  • Base Diameter: .470 inches
  • Case Length: 2.015 inches
  • Overall Length: 2.800 inches

As the specifications show, the .308 Winchester is a larger cartridge overall, accommodating a heavier bullet and more powder. This size difference contributes significantly to the performance differences between the two.

Ballistics and Performance

The ballistic performance of a cartridge is crucial for determining its suitability for various applications. Here’s a comparison of key ballistic characteristics:

Velocity and Energy

6.8 SPC: Typically, a 110-grain 6.8 SPC bullet fired from a 16-inch barrel achieves a muzzle velocity of around 2,550 fps and a muzzle energy of approximately 1,590 ft-lbs. This cartridge excels in close to medium ranges, offering a flatter trajectory than the 7.62x39mm and improved terminal ballistics compared to the 5.56x45mm.

.308 Winchester: A 150-grain .308 Winchester bullet from a 24-inch barrel typically reaches a muzzle velocity of around 2,820 fps and a muzzle energy of approximately 2,650 ft-lbs. The .308 Winchester offers significantly greater energy and a flatter trajectory at longer ranges due to its larger case capacity and heavier bullets.

Trajectory

The trajectory of a bullet is its path through the air. A flatter trajectory means the bullet drops less over a given distance, making it easier to hit targets at varying ranges. The .308 Winchester generally exhibits a flatter trajectory than the 6.8 SPC, especially at distances beyond 300 yards.

Recoil

Recoil is the force felt by the shooter when a firearm is discharged. The 6.8 SPC produces less recoil than the .308 Winchester, making it more comfortable to shoot, especially in semi-automatic rifles. This reduced recoil can lead to faster follow-up shots and improved accuracy for some shooters. The 6.8 SPC is often favored by those sensitive to recoil.

Applications

The 6.8 SPC and .308 Winchester are used in a variety of applications, each cartridge excelling in different areas.

Hunting

6.8 SPC: The 6.8 SPC is suitable for hunting medium-sized game such as deer and hogs within reasonable ranges (out to around 300 yards). Its lighter recoil and adequate energy make it a viable option for hunters who prefer a lighter rifle. However, for larger game or longer ranges, the .308 Winchester is generally a better choice.

.308 Winchester: The .308 Winchester is a versatile hunting cartridge capable of taking down a wide range of game, from deer and elk to bear and moose. Its high energy and excellent terminal ballistics make it effective at longer ranges. Many hunters consider the .308 a good all-around cartridge for North American big game.

Target Shooting

6.8 SPC: While capable of target shooting, the 6.8 SPC is not as commonly used for long-range precision shooting as the .308 Winchester. Its ballistic performance is better suited for shorter to medium-range targets.

.308 Winchester: The .308 Winchester is a popular choice for target shooting, particularly in long-range competitions. Its inherent accuracy and availability of match-grade ammunition make it a top contender in precision shooting disciplines. [See also: Best Long Range Cartridges]

Tactical and Military Applications

6.8 SPC: The 6.8 SPC was originally developed for military applications to improve the performance of the M4 carbine. While it saw some limited use, it never fully replaced the 5.56x45mm NATO round. The 6.8 SPC offers better stopping power than the 5.56 in close to medium-range engagements.

.308 Winchester: The .308 Winchester (7.62x51mm NATO) has a long history of military use, serving as a standard cartridge for rifles and machine guns. Its effectiveness in combat situations has been well-documented. It continues to be used in sniper rifles and general-purpose machine guns around the world.

Availability and Cost

The availability and cost of ammunition are important considerations when choosing a cartridge.

6.8 SPC: The 6.8 SPC is less common than the .308 Winchester, and ammunition can be more expensive and harder to find. This limited availability can be a drawback for high-volume shooters.

.308 Winchester: The .308 Winchester is one of the most popular cartridges in the world, and ammunition is widely available at various price points. This widespread availability makes it a more practical choice for many shooters. You can find .308 ammo in virtually any gun store.

Rifle Platforms

The choice of cartridge often depends on the rifle platform. Here’s a look at the rifle options available for each.

6.8 SPC: The 6.8 SPC is primarily chambered in AR-15-style rifles. These rifles are lightweight and modular, making them popular for hunting and tactical applications. Converting an AR-15 to 6.8 SPC typically involves replacing the barrel and bolt.

.308 Winchester: The .308 Winchester is chambered in a wide variety of rifles, including bolt-action rifles, semi-automatic rifles (such as the AR-10), and lever-action rifles. This versatility makes it a popular choice for hunters, target shooters, and tactical users. The AR-10 platform is specifically designed to handle the larger .308 cartridge.

Pros and Cons

Here’s a summary of the pros and cons of each cartridge:

6.8 SPC

Pros:

• Lighter recoil
• Improved stopping power compared to 5.56x45mm
• Suitable for medium-sized game at reasonable ranges

Cons:

• Less common and more expensive ammunition
• Limited long-range performance
• Fewer rifle options compared to .308

.308 Winchester

Pros:

• Excellent long-range performance
• High energy and terminal ballistics
• Widely available and affordable ammunition
• Versatile for hunting, target shooting, and tactical applications
• Numerous rifle options

Cons:

• Greater recoil
• Larger and heavier rifles

Conclusion

In the 6.8 SPC vs .308 debate, the best choice depends on your specific needs and priorities. The 6.8 SPC offers a good balance of power and recoil in a lightweight platform, making it suitable for medium-range hunting and tactical applications. The .308 Winchester, on the other hand, provides superior long-range performance, high energy, and versatility for a wide range of applications. Consider your intended use, budget, and recoil tolerance when making your decision. Both cartridges are capable in the right hands and for the right purpose. Ultimately, the decision hinges on understanding their respective strengths and weaknesses within the context of your shooting activities. The 6.8 SPC is a specialized cartridge, while the .308 is a general-purpose powerhouse.