Zeus Arms | PROTEUS PSTL 5.56/300BLK | Black Brace

The Zeus Arms PROTEUS PSTL is a compact AR-style pistol designed for modularity and short-range utility. It uses a QD removable barrel system and a foldable SBA3 brace to enable compact transport and quick caliber transitions between compatible barrels. The build centers on mil-spec components, forged 7075-T6 receivers, and a range-focused parts kit manufactured in the U.S. For optics, a rugged compact red-dot such as an Aimpoint PRO or a similar reflex sight under $1,000 pairs well for fast target acquisition and durability.

Product Specifications

• The model is listed as ZEUS ARMS PROTEUS PSTL 5.56/300BLK BLACK BRACE.
• The lower receiver is a GHOST lower machined from 7075-T6 aluminum with a Type III hard coat anodized finish.
• The barrel options include a 7.5-inch 5.56 NATO configuration and an 8-inch 300 Blackout configuration.
• The barrels are manufactured from 4150 CMV and feature a 1:7 RH twist.
• The barrels receive a black nitride finish and are stress relieved after rifling.
• The muzzle device is a flash can machined from 7075-T6 aluminum and is threaded 1/2-28.
• The handguard is machined from 6061-T6 aluminum with M-LOK mounting points at 3:00, 6:00, and 9:00 and a top rail length of 7-9 inches.
• The pistol ships with an SB Tactical SBA3 (Black) brace.
• Included magazine is a Lancer 30-round with hardened steel feed lips and a stainless steel spring.
• The upper receiver is machined from 7075-T6 aluminum and is hard coat anodized.
• The bolt carrier group uses an 8620 M16-style carrier with a black nitride finish and a Carpenter 158 bolt.
• The ambidextrous charging handle is manufactured from a 7075-T6 forging and hard coat anodized.
• Gas system components are machined from 4140 pre-hardened steel and receive a black nitride coating.
• The buffer tube kit uses a mil-spec 7075-T6 six-position buffer tube configured with a carbine buffer and side folding attachment.
• The UPC is 670724648101.

Compact, modular, and built around U.S.-made components, the Proteus PSTL is tailored for shooters who need a transportable AR-pattern platform with quick caliber flexibility. Its removable-barrel system and folding brace make it well suited to backpack carry or vehicle/field use and to short-range, caliber-flexible range sessions and training. Robust materials and nitride finishes are chosen for straightforward serviceability and consistent function under routine use.