14.5" 300 Blackout stainless barrel --1 in 7" twist improved polygonal rifling --300 BLK Noveske Match chamber --Extended feed ramps --Bead blasted finish --Pistol length gas system --Gas tube --Pinned Low Profile Gas Block --5/8x24 threads --Medium Contour Weight: 31oz The Noveske 300 AAC BLACKOUT is designed to run optimally firing both subsonic suppressed and supersonic unsuppressed. This barrel is tuned to lock back on the last round using subsonic 220 and 208 grain ammunition with a sound suppressor. The firearm may not lock back with subsonic 220 and 208 grain ammunition without a sound suppressor. Also, the subsonic 300 BLK ammunition is more susceptible to a malfunction due to carbon fouling and adverse conditions than supersonic ammunition. The barrel is tuned to operate correctly with the back pressure provided by the AAC 762-SDN-6 using an H2 buffer, or a Surefire 762K suppressor and an H buffer. In the development of this barrel, we found evidence that the suppressor may require a symmetrical baffle stack as found in the AAC Cyclone K, 762-SDN6, and Surefire 762K suppressor. Suppressors which cause off axis turbulence, such as those with K type baffles, may cause baffle strikes and/or point of impact shift, and may damage your suppressor. Noveske Rifleworks LLC and Operation Parts will not be responsible for damage or injury under ANY circumstances. Consult you suppressor manufacturer to determine if your suppressor is suitable for this application. Barrel installation should be performed by a qualified gunsmith. Installation of the gas block dowel pin and gas block is required to complete the assembly process. All NFA Regulations apply. Please check your local and state laws before ordering. Contact your local ATF Field Office with any NFA questions you may have.