Maxim Defense PDX 505-SPS 300 Blackout 5.5" Barrel Urban Grey

The Maxim Defense PDX 505-SPS delivers maximum firepower in a compact platform, engineered for professionals who demand reliability in close-quarters scenarios. This 300 Blackout configuration combines the proven PDX platform with optimized barrel length for enhanced maneuverability without sacrificing ballistic performance.

What Makes This Different

Built on Maxim Defense's proprietary PDX system, this firearm integrates a monolithic upper receiver with M-LOK compatibility throughout the handguard. The 5.5-inch barrel length provides optimal velocity for 300 Blackout ammunition while maintaining subsonic performance with suppressed configurations. Factory testing demonstrates consistent sub-2 MOA accuracy at 100 yards with quality ammunition.

Key Features

• 300 AAC Blackout chambering optimized for both supersonic and subsonic loads
• 5.5-inch barrel with 1:7 twist rate for enhanced bullet stabilization
• 20+1 round capacity with standard STANAG magazine compatibility
• Urban Grey Cerakote finish rated for 2,000+ hour salt spray resistance
• M-LOK handguard system with full-length top rail for optics mounting
• Ambidextrous controls including safety selector and magazine release
• Compatible with standard AR-15 triggers, grips, and stocks

Field performance testing shows reliable cycling across temperature ranges from -20°F to 140°F with various ammunition weights. The platform excels in law enforcement applications, home defense scenarios, and suppressed shooting where compact dimensions matter. Consistent ejection patterns and minimal fouling contribute to extended maintenance intervals during high-round-count training sessions.

Technical Specs

• Caliber: 300 AAC Blackout (.300 BLK)
• Barrel Length: 5.5 inches
• Overall Length: 23.5 inches (estimated with standard stock)
• Weight: 6.2 pounds (unloaded, approximate)
• Magazine Capacity: 20+1 rounds
• Finish: Urban Grey Cerakote on metal components
• Handguard: M-LOK compatible aluminum
• Twist Rate: 1:7 inches
• Thread Pitch: 5/8x24 TPI
• Manufacturing: Made in USA

Maxim Defense backs this platform with rigorous quality control standards and materials sourcing from tier-one suppliers. The PDX 505-SPS represents proven engineering focused on professional applications where reliability cannot be compromised.