Introducing the Dirty Bird Dirty Bird 10.3″ 5.56 NATO Carbine Length 416R Barrel – Nitride When it comes to building a rifle you can depend on, one of the areas you cannot afford to skimp on is a high-quality barrel. Along with a high-quality bolt carrier group, the barrel you select is truly the heart of your AR. Knowing this, Dirty Bird Industries has worked to create a barrel that meets the needs of a majority of today’s AR builders. With Dirty Bird’s relentless focus on quality and attention to detail, this versatile barrel is an ideal start for your next AR build.