What's in the Box Maxim Defense MDX:508 300 Blackout Semi-Auto Pistol Cable Lock Owner's Manual The PDX redefined compact firepower in size, durability, and accuracy. With the same heart and soul of the proven PDX, the 508 features an 8.5 barrel, ideal for when maximum concealment and compactness are essential but not as crucial. The 8.5 barrel delivers higher velocities while the CQB system plays a key role in the compact size. The CQB brace adds a mere 5.375 to the end of the receiver with a full extension of 10 , providing complete comfort to the operator. Our proprietary bolt carrier group and buffer & spring options ensure extreme durability and smooth cycling. Our MDX series firearms are also equipped with the Maxim s HATEBRAKE muzzle booster. This patent-pending device significantly reduces recoil, decreases the flash signature, pushes gasses and concussion waves downrange away from the operator, and improves overall performance. Firearm Features HATEBRAKE installed under handguard MOA accurate M-slot compatible handguard Military grade materials Purposefully built for each available caliber All components are MIL-SPEC+ HK height rail for a more rigid upper receiver Military tested rapid deploying PDW stock Optimized low flash and sound signatures Firearm Specifications Manufacturer: Maxim Defense Model: MDX:508 Caliber: 300 Blackout Barrel Length: 5.5" Finish: Arid Type III Anodized