Maxim Defense MDX508-CP 5.56/.223, 8.5″ Barrel, Black, Gen 6 CQB Brace


  • SKU:SHOT-MDX508556
  • BrandMaxim Defense
  • Caliber:223 Remington
  • Caliber:5.56x45mm
  • Model:Maxim MDX-508
  • Unit of Measure:Each
  • Classification:Firearm
  • Interests:New for 2020, Home Defense Guns, AR-15 Pistols
Categories: , Product ID: 5021


The PDX redefined compact firepower in terms of size, durability, and accuracy. The next size up in the MDX family is the 508. 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 important, but not as crucial.

The 8.5″ barrel delivers higher velocities while the SCW stock or brace plays a key role in the compact size. The SCW stock or brace adds a mere 4″ to the end of the receiver with a full extension of 8.75″, 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 in short barrel pistols and rifles.

The MDX-508 will be available in the following options:

7.62x39mm / 5.56 NATO / .300 BLK

Arid / Black

Stock / Brace:


1. SCW or CQB brace or stock
2. Radian Raptor charging handle
3. Ambidextrous QD sling mounts
4. Armorer level adjustable gas block
5. Ambidextrous rear QD sling mount
6. Radian Talon ambidextrous selector
7. BCM Gunfighter grip
8. ALG Defense Combat Trigger
9. Maxim Defense 7075 billet receiver set
10. M-RAX and M-SLOT compatible handguard
11. HATEBRAKE Muzzle Booter


5.56 NATO / .223 Rem

Barrel length 8.5″
Overall length 21.5″ – 23″ (collapsed