Rifling in an AR barrel is one of the most important features for shooting accurately. Somehow this hasn't been the focus on shorter barrels for the pistol market-until now. Fortis is using a process that utilizes their lone rifling technology. they're utilizing a single point cutting technique for greater precision and ultimately, much better accuracy. Concentricity to the bore is unmatched and shows in the shooting experience. Run it harder, faster and more accurately with the Fortis Glock line of barrels. Fits the G19 Gen 1-5 and also fits the 19X.