The Maxim Defense PDX in 300 Blackout uses the same SCW platform and 5.5-inch barrel as the 5.56 variant but chambered in 300 BLK, a cartridge that achieves notably better ballistic performance at suppressed subsonic velocities from short barrels than 5.56x45mm. The PDX 300 BLK is a popular suppressor host due to the 300 BLK subsonic ammunition's suppressed-optimized design. Type: Semi-Auto Pistol Action: Semi-Automatic Caliber: 300 BLK Capacity: 30 Year introduced: 2018, USA Weight: 60 oz Overall length: 20" Status: Active Intended use: home_defense, suppressed_use, special_operations