Maxim Defense PDX 5.56×45 AR Pistol, 5.5 in Barrel, PDW Brace, Radian Raptor-LT, Geissele Maritime Bolt Catch, FosTecH Echo Binary Trigger
This Maxim Defense PDX in 5.56×45 stands out as a compact, purpose-built AR pistol built around the PDX concept that originated from SOCOM's PDW effort and debuted publicly in 2019. It features a 5.5 in barrel with a large blast-forward muzzle device recessed under a short, free-float M-LOK handguard, a collapsing PDW-style brace, and key upgrades including a Radian Raptor-LT ambidextrous charging handle, a Geissele Automatics Maritime Bolt Catch, and a FosTecH Echo AR binary trigger. The lower is marked MD:15 Multi-Caliber and the receiver bears Maxim Defense rollmarks from Saint Cloud, Minnesota, USA.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This firearm is in great shape overall. Minor scratches and blemishes are present on exterior surfaces.
What's Included
- Maxim Defense PDX 5.56×45 AR pistol
- 1x 30-round Mission First Tactical (MFT) polymer 5.56×45 STANAG magazine
Built on the AR-15 platform with a direct impingement system, this PDX-pattern configuration emphasizes ultra-short overall length without sacrificing practical control. The 5.5 in barrel is paired with a large blast-forward muzzle device that is recessed under the handguard to drive blast and concussion forward.
The free-float M-LOK handguard includes integrated QD sling sockets and an integral front hand-stop, and a full-length Picatinny top rail provides continuous mounting space along the upper. The barrel is threaded, and the receiver is aluminum with a matte black anodized finish.
Controls and handling are enhanced with premium components: a Radian Raptor-LT ambidextrous charging handle and a Geissele Automatics Maritime Bolt Catch are installed. A manual safety selector is present, and the brace is a collapsing PDW-style unit with dual guide rods and a rear strap.
The FosTecH Echo AR binary trigger is installed, offering a distinct fire-control upgrade. The lower receiver is marked MD:15 Multi-Caliber while configured here as a PDX-pattern AR pistol. Rollmarks include MAXIM DEFENSE SAINT CLOUD, MINNESOTA USA and 5.56×45. Capacity is 30+1, and one Mission First Tactical polymer magazine is included.