This Rosco 8.2″ 300 Blackout Bloodline Barrel is designed for SBR and pistol use with suppressors. It is the shortest option from Rosco, offering the flexibility of a shorter Personal Defense Weapon (PDW) without sacrificing performance or ballistics. ALL NFA RULES APPLY! Rosco 300 Blackout barrels are made with input from SOCOM end users and some of the original creators of the 300 Blackout caliber. Each barrel is designed to optimize the original purpose of the caliber: being suppressor-friendly and accurate. The goal is to deliver the performance you expect from these AR-15 barrels when using either subsonic or supersonic ammo (depending on barrel length). Twist rates, gas port diameters, and lengths have all been carefully considered during design. Let’s just say that Rosco doesn’t leave anything to chance.