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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.
Prices checked
FN America FN AR-15 Bb M4 Barrel 16 Carbine 5.56mm ranked #131 of the 329 barrels builders added on GunPartPicker in October 2026. Builders have added it to their builds on GunPartPicker. Since April 2026, it ranks #44 of the 1,042 barrels builders have added.
Availability is good: it was in stock at one retailer or another nearly every time we checked in October 2026, and today 5 of the 6 retailers we track have it in stock. It dipped to $199.73 at KY Gun Company for a stretch in October 2026, well under its usual $279, so sales do come around. Buying today, the lowest price is $199.73 at KY Gun Company, which matches the best price we saw in October.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
We ranked every barrel by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Barrel Length & Brand Report →Check it against the live catalog:
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