Maxim Defense MXM50840 PDX 505-SPS 7.62x39mm 5.50in

Description

The Maxim Defense MXM50840 PDX 505-SPS 7.62x39mm 5.50in is a purpose-built AR-pattern pistol that pairs a compact 5.50-inch barrel with Maxim’s own SCW Pistol System to create a snag-free, lightweight rear profile. Chambered in 7.62x39mm, this pistol delivers reliable cycling and hard-hitting ballistics in a package that’s short enough for vehicle, pack, or close-quarters carry. The SCW Pistol System shaves over 10 ounces compared to Maxim’s standard SCW stock, bringing total rear-end weight down to roughly 5.3 ounces.

Manufacturer	Maxim Defense
Model	MXM50840 PDX 505-SPS
Material	7075-T6 aluminum upper and lower receiver per manufacturer specs
Compatibility	Standard AR-15 lower with 7.62x39mm bolt and magazine
Finish	Hardcoat anodized black
Weight	5.3 ounces (SCW Pistol System only); overall weight not published
Condition	New

Key Features

• SCW Pistol System – Replaces the standard brace with a slim, snag-free rear profile that cuts over 10 ounces from the back end, improving balance and handling in tight spaces.
• 5.50-inch Barrel – Short enough for concealed or vehicle carry yet still delivers the velocity needed for reliable 7.62x39mm expansion and terminal performance.
• Single-Point QD Mount – A rear-facing quick-detach sling swivel is built into the SCW system, letting you attach a single-point sling without extra hardware or bulk.
• 7.62x39mm Chamber – Uses standard commercial ammunition, giving you the same stopping power as an AK in a familiar AR platform without needing exotic magazines or bolts.
• Compact Overall Length – At just over 20 inches collapsed, this pistol fits in packs, vehicle consoles, and range bags while staying ready for immediate use.

Who It’s For

This Maxim Defense pistol is built for shooters who need a compact, reliable 7.62x39mm platform for truck, backpack, or home defense. It suits traditionalists who value a proven cartridge and modernists who want AR ergonomics in a short package. If you appreciate well-machined aluminum, tight tolerances, and a system that shaves weight without sacrificing durability, this one’s for you.

Pros & Cons

• Pro: SCW Pistol System drops rear weight by over 10 ounces, making the pistol easier to maneuver one-handed.
• Pro: Snag-free profile and QD sling mount mean no loose straps or sharp edges to catch on gear.
• Con: At 5.50 inches, the barrel is too short for long-range accuracy; expect a 100-yard practical limit.
• Con: 7.62x39mm ammunition is heavier and more expensive than 5.56mm, which may deter high-volume plinking.

Comparison: Maxim Defense PDX vs. Zev Technologies OZ9 vs. Agency Arms ATOM

Feature	Maxim Defense PDX 505-SPS	Zev Technologies OZ9	Agency Arms ATOM
Caliber	7.62x39mm	9mm	9mm
Barrel Length	5.50 in.	4.5 in.	5.0 in.
Weight (pistol system)	5.3 oz (rear only)	~8.5 oz (complete)	~9.2 oz (complete)
Platform	AR-pattern	Striker-fired	Striker-fired
Price	$2,245.50	$1,899.99	$2,599.00

The PDX gives you a rifle-caliber advantage in a pistol-sized package, while the OZ9 and ATOM are limited to 9mm. The trade-off is weight and ammo cost.

FAQ

What magazines does the Maxim Defense MXM50840 PDX use?

It accepts standard 7.62x39mm AR magazines, such as those made by C-Products or ASC. Always verify feed-lip compatibility with your specific bolt.

Is the SCW Pistol System legal as a pistol brace?

Yes, the SCW Pistol System is designed as a pistol brace and complies with current ATF rulings as of April 2026. Check local laws for any changes.

Can I suppress this pistol?

The 5.50-inch barrel is threaded 1/2×28, so you can attach a suppressor. Keep in mind that 7.62x39mm subsonic ammunition is limited and may not cycle reliably without tuning.

How does the PDX compare to an AK pistol in the same caliber?

The PDX uses AR-standard controls and triggers, which many shooters find more familiar than AK ergonomics. It also offers a lighter rear end and better accessory mounting options.

Last updated: April 2026

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