Maxim Defense PDX Complete Upper – 5.56 NATO/.223, 5.5” Barrel, CQB-Optimized, AR-15 Compatible, Ultra-Compact PDW UppeR

Compact. Rugged. Ready. The Maxim Defense PDX Complete Upper in 5.56 NATO/.223 delivers mission-driven performance in an ultra-short profile — all engineered for modern CQB applications and built to thrive in tight environments.

At the heart of this upper is a 5.5” cold-hammer-forged barrel, built to perform under extreme conditions. Paired with the Maxim HATEBRAKE™ muzzle device, this upper redirects gas and sound forward, reducing concussion and improving control during rapid fire.

Whether you’re building a short-barreled rifle (SBR), AR pistol, or PDW, the PDX is compact firepower redefined.

Maxim Defense PDX Complete Upper, 5.56mm/223 5.5″ Barrel, Black

The NEW Maxim Defense PDX U.R.G is built to handle the fierce demands of the Tier 1 community and designed to install on any Mil-Spec lower receiver. With the PDX U.R.G, you dominate close quarter encounters and achieve maximum energy on target without sacrificing accuracy at distance. At just 14″ overall length and a 5.5″ barrel, the PDX U.R.G. is the ultimate choice for when concealment and personal defense is non-negotiable.

The PDX U.R.G. is also equipped with newly invented Maxim HATEBRAKE Muzzle Booster. This patent-pending device significantly reduces recoil, decreases the flash signature, pushes gasses and concussion waves downrange away from the operator improving overall execution in short barrel pistols and rifles. The PDX U.R.G. uses a Direct Impingement system.

FEATURES:

HATEBRAKE installed under handguard
M-slot compatible handguard
Military grade materials [6Al-4V Titanium, 17-4 Stainless Steel, 7075 and 6061 Aluminum]
HK height rail for a more rigid upper receiver
Maxim Mil-Spec BCG

FUNCTIONS :

Optimized Personal Defense Weapon Upper
Increased reliability due to included HATEBRAKE
Optimized low flash and sound signatures
Designed to work with any Mil-Spec lower receiver

• WEIGHT : 4 lbs
• OVERALL LENGTH : 14 inches
• BARREL LENGTH : 5.5 inches
• CALIBER : 5.56, 7.62×39
• MUZZLE THREADS : 5/8-24, 1/2-28
• FINISH : Arid Earth and Black in color Type-III Hard Anodizing

Take your build to the next level with a true duty-proven PDW upper that’s been tested in the harshest conditions — the PDX doesn’t just work, it dominates.

FAQ:

Q: Can I legally run this upper on my AR-15 lower?
A: Yes, but due to the short barrel (5.5”), you’ll need to use it with a registered SBR or AR pistol lower to remain NFA compliant.

Q: Does it come with a bolt carrier group or charging handle?
A: No — the BCG and charging handle are not included, allowing you to choose your own or pair with Maxim’s BCG for optimal performance.

Q: What’s special about the HATEBRAKE?
A: The HATEBRAKE muzzle device significantly reduces felt concussion and blast — making it ideal for indoor use and close-quarters shooting.

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Maxim Defense PDX Complete Upper – 5.56 NATO/.223, 5.5” Barrel, ARID (FDE) Finish, AR-15 Compatible, PDW Compact Upper Receiver