The Maxim Defense PDX 505-SPS 5.56 NATO 5.50" Barrel 20+1 is a compact AR-format pistol that pairs a short 5.50-inch barrel with Maxim’s streamlined SCW Pistol System. This combination reduces the rearward profile and minimizes snag points on gear, making it a practical choice for home defense, vehicle carry, or range training with the family. The package ships in an Urban Grey metal finish with a matching polymer grip and is optic-ready for modern sighting systems.
| Manufacturer | Maxim Defense |
|---|---|
| Model | PDX 505-SPS |
| Material | Forged aluminum receiver, steel barrel |
| Compatibility | .223 REM / 5.56 NATO ammunition, standard AR-15 magazines |
| Finish | Urban Grey metal finish, Urban Grey polymer grip |
| Weight | 5.3 lbs (per manufacturer specs) |
| Condition | New |
Key Features
- Compact 5.50-Inch Barrel — why it matters: Keeps the overall length short for easy handling in tight spaces, yet still chambers 5.56 NATO for effective self-defense.
- SCW Pistol System — why it matters: Reduces the buffer tube length by 2 inches, making the pistol easier to store in a vehicle or safe without sacrificing reliability.
- Urban Grey Finish — why it matters: Resists wear and corrosion while giving your build a distinctive, low-visibility look that matches modern tactical gear.
- Optic-Ready Receiver — why it matters: Lets you mount your preferred red dot or reflex sight without extra gunsmithing, so you can get on target faster.
- 20+1 Round Capacity — why it matters: Provides enough ammunition for multiple threat engagements or extended range sessions without constant reloading.
Who It’s For
This pistol is designed for shooters who value compact handling, modularity, and a manageable balance of capability and control. It suits families looking for a home-defense tool that’s easy for smaller-statured shooters to operate, as well as youth shooters transitioning from .22 LR to centerfire. Beginners will appreciate the reduced recoil impulse from the SCW system, while experienced shooters will enjoy the customization options.
Pros and Cons
- Pro: Extremely compact package — fits in backpacks and vehicle compartments.
- Pro: Reliable feeding and ejection with standard AR-15 magazines.
- Pro: Optics-ready saves you money on milling.
- Con: Short barrel reduces muzzle velocity compared to a 16-inch rifle, so effective range is about 200 yards.
Comparison: Maxim Defense PDX 505-SPS vs. Competitors
| Feature | Maxim Defense PDX 505-SPS | Zev Technologies OZ9C | Agency Arms AOS Glock 19 |
|---|---|---|---|
| Caliber | 5.56 NATO | 9mm | 9mm |
| Barrel Length | 5.50 inches | 4.5 inches | 4.02 inches |
| Capacity | 20+1 | 17+1 | 15+1 |
| Weight | 5.3 lbs | 1.7 lbs | 1.5 lbs |
| Optics Ready | Yes | Yes | Yes |
| Price | $2,245.50 | $1,899 | $1,699 |
According to Maxim Defense specs, the PDX 505-SPS is designed for shooters who need a rifle-caliber platform in a handgun-sized package. While the Zev and Agency options are lighter and cheaper, they fire 9mm pistol cartridges. The PDX gives you rifle ballistics in a compact form, which is a trade-off worth considering for home defense.
Frequently Asked Questions
Is the Maxim Defense PDX 505-SPS legal to own without a tax stamp?
Yes, as a pistol with a 5.50-inch barrel and a brace (not a stock), it is classified as a pistol under federal law. Always check your state and local laws, as some states restrict AR-pistol configurations.
Can I use standard AR-15 magazines with this pistol?
Yes, the PDX 505-SPS accepts all standard AR-15/M16 magazines. The included 20-round magazine is compact, but you can use 30-round or larger mags for more capacity.
What optics fit the optic-ready receiver?
The receiver is cut for a standard Aimpoint Micro footprint, but adapter plates are available for Trijicon MRO, Holosun 407C/507C, and other common red dot patterns.
Is this pistol suitable for a beginner shooter?
Yes, the SCW system reduces felt recoil, and the compact size makes it easier to control than a full-length rifle. However, beginners should practice with .223 REM ammunition first and always follow safety rules.
Trust and Service
- ✅ Nationwide delivery (all 50 states)
- ✅ Ships 1-2 business days
- ✅ 30-day returns
- ✅ Secure checkout
Explore more compact options in our AR Pistols collection, or check out AR Uppers for custom builds. You can also browse Firearm Accessories for optics and upgrades.
Last updated: April 2026
FFL Transfer & Firearms Laws for Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1
All firearms, including the Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1, must be shipped to a licensed Federal Firearms License (FFL) dealer. You will be required to complete a background check and any necessary paperwork before taking possession.
How It Works
- Place your order online.
- Provide your preferred FFL dealer information.
- We ship the firearm directly to your FFL.
- You complete the background check and pickup at the FFL.
Legal Compliance
We comply with all federal and state firearm laws. It is your responsibility to ensure the Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1 is legal in your state. Some states may have restrictions on certain firearm models or features.
Helpful Resources
Need assistance? Contact our Miami store for help with FFL transfers and firearm compliance.
Frequently Asked Questions About This Product
Why buy Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1 from Miami Shooters Supply?
We’re a trusted firearms dealer offering fast shipping, competitive pricing, and 100% compliance with U.S. federal firearm laws. All orders ship from our licensed facility with full tracking and expert customer service.
Where can I buy Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1?
You can purchase this item directly on our website and have it shipped to your local FFL dealer. You can also visit us in-store in Miami, Florida.
Is Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1 available now?
Availability is shown live on this page. If the “Add to Cart” button is visible, this item is currently in stock and ready to ship.
What category does this product belong to?
This product is listed under: AR Pistols.
What tags or features does this product have?
Key features and tags for this product include: .
Is this product legal in my state?
It is your responsibility to ensure this item is legal in your state or locality. We ship only to valid FFL dealers in compliance with U.S. laws. Always check your local regulations.
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FFL Transfer & Firearms Laws
All firearms, including the Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1, must be shipped to a licensed Federal Firearms License (FFL) dealer. A background check and any required local paperwork must be completed before you can take possession.
How It Works
- Place your order online.
- Send us your preferred local FFL dealer info.
- We ship the firearm to your FFL after verification.
- Complete background check and pick up from your dealer.
Legal Compliance
We comply with all U.S. firearm laws. It is your responsibility to ensure the Maxim Defense PDX 505-SPS 5.56 NATO 5.50″ Barrel 20+1 is legal in your state. Some states (e.g. CA, NY, NJ) have restrictions on magazine size or certain features.
Helpful Links
Need help? Contact our team — we’ll guide you through selecting a compliant firearm and the FFL transfer process.
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