The FN 15 rifle series is based on FN's semi-automatic, direct impingement platform for the 5.56x45mm, .223 Remington, and .300 AAC Blackout (7.62x35mm) cartridges, and offers something for everyone, whether the application is tactical, collector, or target/competition. At the core of each FN 15 is a hard-anodized aluminum, flat-top receiver, featuring a M1913 MIL-SPEC rail at the 12 o’clock position. Barrel length (chrome-lined) varies from 16" to 18".