Pro2a Tactical offers a large selection of 300 Blackout AR-15 Upper Assemblies. 300 Blackout is the perfect caliber for short/medium range applications and is the perfect round to be suppressed. We offer the 300 Blackout in a variety of barrel lengths, twists, gas systems, muzzle devices and formats to suit your needs. All of our complete uppers are assembled by the most experienced armorers and covered by our limited lifetime guarantee.