The Advanced Armament MPW 9" 300blk SBR is designed as a multi purpose weapon system using the 300blk cartridge which gives you a larger 30 caliber in the same platform and magazine capacity as a typical 5.56x45mm AR15. The huge benefit of the 300blk cartridge is the ability to quickly interchange super quiet subsonic ammunition for use with a suppressor and be quieter than a 9mm MP5 or supersonic which has more energy than a 7.62x39 when you need to reach out and touch someone. The AAC MPW is made from the highest quality materials, Milspec receivers are machined and finished to provide an excellent foundation for the high quality parts. 1:7 twist Nitrated barrel provides hardness and accuracy far above a typical chrome lined barrel and is threaded 5/8x24 with a AAC 51T flash hider for mounting a suppressor, the Knights Armament URXIII free floating rail gives you a rigid mounting platform for lights, lasers, or vertical grips. The Bolt carrier group is machined from hardened steel and the bolt head itself is 158 carpenter steel. The trigger is a Geisselle which is renowned for their super high quality and this trigger is no exception. This AAC MPW 9" 300blk is a Class 3 firearm and requires the appropriate $200 tax stamp before taking possession.