Maxim Defense PDX Upper | 5.56 NATO | 5.5 in

The Maxim Defense PDX complete upper is a compact AR upper built around a 5.5-inch barrel and a Direct Impingement gas system. It features Maxim’s HATEBRAKE muzzle booster and is designed to install on any Mil-Spec AR lower receiver. The assembly yields an overall length referenced at 14 inches, optimized for short-barrel AR configurations without adding unnecessary complexity.

Product Specifications

• The manufacturer is Maxim Defense Industries.
• The model is identified as PDX.
• The caliber is .223 Rem / 5.56 NATO.
• The barrel length is 5.5 inches.
• The overall length is stated as 14 inches.
• The action uses a Direct Impingement gas system.
• The upper is equipped with the Maxim HATEBRAKE Muzzle Booster.
• The finish/color is listed as Black.
• The fitment is for AR rifles (Mil-Spec lower).
• The product type is Complete Upper Receiver.
• The subcategory is Complete Upper Receivers.
• The product is described as designed to install on any Mil-Spec lower receiver.
• The intended applications include short-barrel AR configurations for training and tactical practice.
• The image URL on file is https://garidium.s3.amazonaws.com/product-details/rsr/images/MXM-47813_1.jpg.
• The UPC is 680017478131.

The PDX upper is a compact, purpose-built option when a short-barrel AR configuration is required. Its Direct Impingement system and integrated muzzle booster provide a predictable platform for range training and tactical/competition scenarios that benefit from reduced overall length. The build emphasizes straightforward installation on mil-spec lowers and practical ergonomics for controlled handling.