The Maxim Defense PDX is an AR-pattern firearm chambered in .300 AAC Blackout with a 5.5-inch barrel and a 20-round capacity. It ships in a black finish. The 5.5-inch barrel is a short-barreled configuration; transfer requires additional federal paperwork. 
 

Key Specifications 

• Brand: Maxim Defense 
• Model: PDX 
• Caliber: .300 AAC Blackout 
• Action: Semi Auto 
• Capacity: 20rd 
• Barrel Length: 5.5 in 
• Color/Finish: Black 
   

Detailed Features 

• AR-pattern platform chambered in .300 AAC Blackout 
• 5.5-inch barrel in a short-barreled configuration requiring additional federal paperwork 
• 20-round magazine included 
• Black finish throughout

Owners of the Maxim Defense PDX in .300 AAC Blackout typically point to the compact form factor as the main draw. The 5.5-inch barrel makes it genuinely small, and the .300 AAC Blackout chambering gives it more punch than a comparable 9mm PCC at that length. Most feedback centers on how well the platform handles both supersonic and subsonic loads.

Ergonomics split opinion. The PDX's proprietary buffer system is praised for keeping the package tight, but some owners find the controls unfamiliar compared to a standard AR lower. Cheek weld and sight radius at this barrel length require adjustment for shooters coming from full-size rifles.

Value comes up often in discussions. The PDX sits at a premium price point, and buyers generally accept that for the engineering involved. The common complaint is parts availability: Maxim-specific components aren't as easy to source as standard AR parts, which matters when something needs replacing.