FN AR-15 Bb M4 Barrel 16 Carbine 5.56mm
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FN America
Overview
The FN AR-15 M4 Barrel features a 16-inch length and a carbine gas system, designed specifically for the 5.56 NATO caliber. With an M4 profile and a 1:7 twist rate, this barrel is optimized for stabilizing a wide range of bullet weights, making it a versatile choice for various shooting applications. This barrel commonly appears in tactical and sport shooting builds, where reliability and performance are key considerations.
Specifications
August 2026 on GunPartPicker
FN America FN AR-15 Bb M4 Barrel 16 Carbine 5.56mm ranked #34 of the 298 barrels builders added on GunPartPicker in August 2026. Builders have been adding it to their builds on GunPartPicker since May 2026. All time, it ranks #27 of the 812 barrels builders have added.
Availability is good: it was in stock at one retailer or another nearly every day in August 2026, and today 4 of the 6 retailers we track have it in stock. The best price drifted down from $279 to $199.73 over August 2026 without a real sale. Buying today, the lowest price is $199.73 at KY Gun Company, which matches the best price we saw in August.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 35 retailers
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Frequently Built With
The part most often added in each category by the 8 builds that include this one
Bravo Company M16 Bolt Carrier Group Black
Bravo Company Mfg M1913 Picatinny 12" Quad Rail Free Float Handguard, Black - QRF12556BLK
Centurion Arms CM4 5.56 Forged AR-15 Lower Receiver
BCM Ambidextrous MK2 Large Latch Charging Handle, Black - Easy Operation with Superior Control - GFH-MK2-LRG-AMBI
PSA AR-15 Built Stealth Upper Receiver - No T Marks - 516444539
Sons of Liberty Gun Works AR-15 Gas Tube Stainless Steel Carbine
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
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