The 22Mods4All SA9 'Stinger PDW' Series Complete 9mm Upper Receiver is built from the ground up to provide outstanding reliability and accuracy with a host of top tier features. The SA9 'Stinger PDW' combines the popular performance and low cost of the 9mm round with the compact, high quality reliability of the short nitride barrel only the popular Bear Creek Arsenal can provide. Lastly, the slim-line Handguard, built by Daytona Tactical, is ultra-lightweight, free-floating with a monolithic top-rail. This handguard comes built from heavy-duty T6 aluminum and is compatible for your favorite accessories. All of our 9mm uppers use a blow-back gas system removing the need for traditional gas systems. The Anderson Manufacturing upper receiver for this 9mm upper is slick-sided unique to this pistol caliber. Bolt and Upper is fully cut and compatible with Last Round Bolt Hold Open (LRBHO) technology that allows for reliable bolt lock back when combined with a Glock magazine compatible lower.