This Rosco 8.2"" 300 Blackout Bloodline Barrel was designed for SBR and Pistol use in conjunction with suppressors. This is the shortest that we will go to allow you the flexibility of a shorter Personal Defense Weapon (PDW) without sacrificing performance or ballistics. ALL NFA RULES APPLY! Rosco 300 Blackout barrels were created by using input from SOCOM end users and some of the original creators of the 300 Blackout caliber. Every barrel was designed to optimize the original role for this caliber