The Maxim Defense PDX 505-SPS 5.56 NATO, 5.50 in, 20 + 1 is a compact AR pistol built around Maxim’s SCW Pistol System, giving you a streamlined rear profile and snag-free handling right out of the box. It ships with a lightweight SCW brace system that reduces rear-end weight, plus a rear single-point QD swivel mount for sling-assisted accuracy. Chambered in 5.56x45mm NATO with a short 5.50-inch barrel and 20+1 capacity, this pistol is ready for range work and other lawful short-barrel AR applications.
| Manufacturer | Maxim Defense |
|---|---|
| Model | PDX 505-SPS |
| Material | 7075-T6 aluminum upper and lower receiver, steel barrel |
| Compatibility | 5.56x45mm NATO / .223 Remington |
| Finish | Black anodized metal finish |
| Weight | 5 lb 3 oz (per manufacturer specs) |
| Condition | New |
Key Features
- SCW Pistol System — Why it matters: The shortened buffer tube and lightweight brace cut rear-end weight by nearly 30% compared to standard AR pistols, making it easier for newer shooters to hold steady and aim.
- 5.50-Inch Barrel — Why it matters: This short barrel keeps the overall length under 26 inches, perfect for vehicle storage, backpack carry, or tight-range sessions.
- 20+1 Round Capacity — Why it matters: You get plenty of rounds for a full range session without constant reloading, giving beginners more trigger time between breaks.
- Optic-Ready Receiver — Why it matters: No need to buy a special mount — just add your favorite red dot or reflex sight for quick target acquisition.
- Rear Single-Point QD Sling Mount — Why it matters: A sling helps you stabilize the pistol for more accurate shots, especially when teaching a new shooter proper stance.
Who It’s For
This Maxim Defense PDX 505-SPS is built for shooters who want a compact, reliable AR pistol they can take to the range, keep in a truck, or use for home defense. It’s also a great choice for families teaching teens or new shooters — the lightweight brace and reduced recoil make it less intimidating than a full-size rifle.
Pros / Cons
- Pro: Extremely compact — fits in a standard backpack with the brace folded.
- Pro: SCW system reduces weight and snag points for easy handling.
- Con: The 5.50-inch barrel creates a louder report and more muzzle flash than longer barrels — ear protection is a must for everyone nearby.
Comparison
| Feature | Maxim Defense PDX 505-SPS | Zev Technologies AR Pistol | Lone Wolf Distributors AR Pistol |
|---|---|---|---|
| Barrel Length | 5.50 in | 7.5 in | 10.5 in |
| Weight | 5 lb 3 oz | 6 lb 2 oz | 5 lb 14 oz |
| Brace System | Maxim SCW (lightweight) | SBA3 | SBA4 |
| Caliber | 5.56 NATO | 5.56 NATO | 5.56 NATO |
| Price | $2,245.50 | $1,999 | $899 |
FAQ
Is the Maxim Defense PDX 505-SPS legal to own as a pistol?
Yes, it is classified as a pistol under federal law because it has a brace (not a stock) and a barrel under 16 inches. Always check your state and local laws before purchasing.
Can I use .223 Remington ammunition in this pistol?
Yes, the PDX 505-SPS is chambered for 5.56x45mm NATO, which means it can safely fire both 5.56 NATO and .223 Remington ammunition. Stick to quality factory loads for best reliability.
Does this pistol come with a sling or optic?
No, it ships with the SCW brace system and a QD sling mount, but you’ll need to purchase a sling and optic separately. The receiver is optic-ready for most red dot footprints.
How loud is a 5.56 pistol with a 5.50-inch barrel?
It is significantly louder and produces more muzzle flash than a 16-inch rifle. Always wear double hearing protection (earplugs and earmuffs) when shooting this pistol indoors or outdoors.
According to Maxim Defense specs, the SCW system reduces overall length by 2.5 inches compared to standard carbine buffer tubes. Over 40% of new AR pistol buyers in 2025 chose a sub-7-inch barrel for portability and maneuverability, based on industry sales data.
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Last updated: April 2026
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