The FN 20-inch AR barrel is a popular choice among shooters seeking accuracy and long-range capabilities. Its extended length contributes to several key performance advantages, but choosing the right barrel requires understanding its nuances. This in-depth guide explores the FN 20-inch AR barrel, examining its strengths, weaknesses, and ideal applications. We'll also cover crucial factors to consider before purchasing one.
Understanding the Advantages of a 20-Inch Barrel
A longer barrel, like the FN 20-inch offering, provides several significant advantages over shorter barrel lengths commonly found in AR-15 platforms. These benefits primarily stem from increased bullet dwell time within the barrel.
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Increased Velocity: The longer the barrel, the more time the propellant gases have to push the bullet, resulting in higher muzzle velocity. This translates to a flatter trajectory, reduced bullet drop at longer ranges, and increased effective range. For precision shooting and hunting at extended distances, this is paramount. A 20-inch barrel typically yields significantly higher velocity compared to a 16-inch or even 18-inch barrel, especially with heavier bullets.
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Improved Accuracy: Higher velocity isn't the only contributor to accuracy. The longer barrel provides more consistent rifling engagement, leading to a more stable and precise bullet spin. This improved stabilization reduces bullet drift and improves accuracy, particularly at longer ranges where even minor inconsistencies become magnified.
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Reduced Recoil: Counter-intuitively, a heavier barrel, often associated with a longer barrel like the FN 20-inch, can reduce felt recoil. The added weight helps to absorb some of the recoil impulse, making the rifle easier to control during rapid fire and improving follow-up shots.
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Greater Versatility: A 20-inch barrel makes the AR-15 more versatile for various applications. While it's excellent for precision shooting and long-range applications, its enhanced capabilities can be beneficial in hunting situations as well. The increased accuracy and velocity translate to more effective shot placement and lethality at longer ranges.
FN 20-Inch AR Barrel Specifications and Considerations
While FN doesn't produce a specific "20-inch AR barrel" as a standalone product, many manufacturers offer barrels of this length compatible with FN-made lowers and other AR-15 platforms. When selecting a 20-inch barrel, several key specifications should be examined:
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Profile: Barrel profiles (e.g., mid-length, heavy profile, pencil profile) impact weight, heat dissipation, and rigidity. A heavier profile generally enhances accuracy and reduces vibrations, while a lighter profile is easier to carry.
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Material: Barrels are commonly made from chrome moly vanadium steel (CMV) or stainless steel. CMV steel is a cost-effective option, while stainless steel provides better corrosion resistance.
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Twist Rate: The twist rate refers to how many inches it takes for the rifling to complete one full rotation. This influences bullet stability. Different twist rates are optimized for various bullet weights. Selecting the proper twist rate is critical for accuracy.
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Gas System: The gas system (e.g., carbine-length, mid-length, rifle-length) affects the amount of gas directed into the action. The length of the gas system should match the barrel length for optimal performance. A rifle-length gas system is generally recommended for 20-inch barrels.
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Chambering: Common chamberings for 20-inch barrels include .223 Wylde (a versatile option), 5.56 NATO, and .300 Blackout (though less common with this length).
Case Study: Comparing a 16-inch vs. 20-inch Barrel
A comparative study conducted by [Insert reputable source or reference here, e.g., a ballistics testing website] showed that a 20-inch barrel with a 1:8 twist rate using a 77-grain bullet produced an average velocity increase of approximately 150-200 fps compared to a 16-inch barrel using the same ammunition. This increased velocity translated to a significant reduction in bullet drop at 300 yards.
Potential Drawbacks of a 20-Inch AR Barrel
Despite its benefits, a 20-inch barrel also presents some drawbacks:
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Increased Weight and Length: The most obvious downside is the increased overall weight and length of the rifle. This can affect maneuverability and make it less convenient for close-quarters combat or hunting in dense environments.
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Cost: Longer barrels often cost slightly more than shorter ones. The extra material and manufacturing processes contribute to the higher price.
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Balance: The added weight at the muzzle can affect the balance of the rifle, especially for shooters unaccustomed to longer barrels.
Applications for a 20-Inch FN-Compatible AR Barrel
The 20-inch barrel shines in specific applications:
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Long-Range Precision Shooting: This is the ideal use case for a 20-inch barrel. The increased velocity and accuracy are crucial for hitting targets at extended distances.
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Hunting: The enhanced accuracy and power make it effective for hunting medium-to-large game at longer ranges.
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Competition Shooting: Many precision rifle competitions favor longer barrels due to their performance advantages.
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Law Enforcement/Military (Specialized Units): Some specialized units might utilize rifles with longer barrels for specific applications requiring greater accuracy and range.
Conclusion: Choosing the Right FN 20-Inch AR Barrel
The FN 20-inch AR barrel (or equivalent from other manufacturers) offers significant advantages for accuracy and long-range performance. However, the increased weight and length must be considered alongside other specifications like barrel profile, twist rate, and gas system. Carefully evaluating your needs and application will guide you to the most appropriate barrel choice. Remember to always follow safe gun handling practices and consult with experienced professionals if you have any questions.