Maxim Defense MDX:505 PDX 7.62x39 SBR, 5.5 inch Barrel, Direct Impingement, SCW 5-Position Stock
This Maxim Defense MDX:505 PDX stands out as a compact, direct-impingement AR-15 chambered in 7.62x39 with a 5.5 inch barrel and factory overall length of 18.75 inches collapsed. It features billet 7075-T6 receivers, a free-float M-LOK/M-Slot-style handguard with QD sockets, and a full-length 1913 top rail. Notable enhancements include an ambidextrous charging handle and safety, a slick-side upper without forward assist, a large blast-diffuser/linear compensator, and a Maxim enhanced firing pin tuned for 7.62x39 ignition.
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.
Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This firearm is in great shape overall. Minor and superficial scratches and blemishes are present on the exterior. The bore is clean and shiny.
What’s Included
- 1x 20-round AR-pattern 7.62x39 steel magazine
- M-LOK Picatinny rail section installed at 6 o'clock on the handguard
The MDX:505 PDX configuration delivers a highly compact 7.62x39 package with a 5.5 inch barrel and factory overall length of 18.75 inches when collapsed. It maintains a full-length 1913 top rail for mounting needs and uses a slick-side upper without a forward assist for a clean profile.
The Maxim SCW collapsing stock provides five positions of adjustment, a skeletonized buttplate, and a textured pad. This stock design enables the short overall length while retaining solid shoulder support and rapid length-of-pull changes.
Construction is centered on durability and rigidity with 7075-T6 billet receivers and an extruded aluminum free-float handguard. The Type III hard-coat anodized finish in matte black protects the aluminum components, and integral QD sling sockets are built into the handguard.
Controls are modern and ambidextrous, including an ambi safety selector and an ambidextrous charging handle with extended levers. The threaded barrel is fitted with a large blast-diffuser/linear compensator, and a Maxim enhanced firing pin supports reliable 7.62x39 ignition on this direct-impingement AR-15 platform.