Sig Sauer MPX 9mm 20 Round Magazine Black Polymer 8900828 UPC 798681661497
Product Description
The Sig Sauer® MPX 9mm 20-Round Black Polymer Magazine (SKU: 8900828 / UPC: 798681661497) delivers uncompromising duty-grade reliability and low-profile maneuverability for the renowned Sig MPX platform. Engineered to combine the lightweight resilience of high-impact polymers with the rigid tolerances of metal submachine gun magazines, this factory-enhanced 20-round magazine optimizes weapon balance and handling. Its compact footprint significantly reduces overall vertical profile compared to standard 30-round magazines, making it the premier choice for discreet backpack staging, vehicle deployment, executive protection details, and home defense setups.
Co-developed in technical partnership with ThrIL, the body is molded from an advanced high-impact elastomeric polymer that retains structural integrity across extreme temperature swings and high-impact field stress. Crucially, the magazine integrates precision-formed stainless steel feed lips directly into the top of the polymer housing. This hybrid construction prevents the lip splay, feed geometry distortion, and fatigue commonly experienced with all-polymer magazines under long-term loaded storage, while shielding feed surfaces from continuous cycling abrasion against the reciprocating MPX bolt carrier group.
The interior column utilizes an anti-tilt, high-lubricity polymer follower driven by a heavy-duty tempered music-wire spring, providing uniform, high-speed upward cartridge presentation in true double-stack, dual-feed configuration. Externally, the magazine features aggressive molded ribbing and tactile texturing along the drive surfaces to ensure immediate indexing and positive purchase during high-stress speed reloads in wet, muddy, or gloved environments. An integrated mechanical over-insertion shoulder prevents excessive upward seating against internal ejector rails, preserving critical host weapon tolerances.
*Armorer Bench Notes & Real-World Staging Guidance:*
Fitment Matrix: Fully compatible with all Sig Sauer MPX variations across Gen 1, Gen 2, and current Gen 3 models, including the MPX K, MPX PCC, and MPX Copperhead. CRITICAL ARMORER NOTICE: The MPX utilizes a true dual-column feed presentation; never attempt to load single-feed loaders or force cartridges into non-compatible subgun platforms. Ensure the magazine seats fully on a closed bolt by applying positive upward palm pressure until the magazine catch firmly clicks past the detent window.
- Ensure the host MPX is pointed in a safe direction, selector set to SAFE, magazine removed, and the chamber visually and physically inspected to verify an empty status.
- Inspect the feed lips of the magazine to verify that the integrated stainless steel reinforcement inserts are clean, uniform, and free of carbon fouling or burrs.
- Load 20 rounds of factory 9x19mm Parabellum ammunition into the dual-feed column, alternating left and right cartridge presentation while ensuring proper rearward rim seating against the back wall.
- With the bolt carrier locked back (or forward), insert the magazine smoothly into the MPX lower receiver until the magazine catch securely locks into the retention notch; verify retention with a firm downward pull.
- Release the bolt catch to chamber a round (or cycle dummy inert rounds on the bench) to confirm smooth dual-feed extraction, reliable follower tracking, and positive last-round bolt hold-open.
Key Features
- Hybrid Steel & Polymer Architecture: Integrates hardened stainless steel feed lips into an impact-resistant polymer body to eliminate feed-lip splay and long-term creep.
- Optimized 20-Round Profile: Delivers high-volume 9mm firepower with a compact vertical envelope, streamlining vehicle deployment and discrete bag storage.
- True Dual-Feed Geometry: Feeds seamlessly from alternating columns directly into the MPX push-feed chamber, matching factory subgun cyclic rates.
- Anti-Tilt Follower System: High-lubricity internal follower and high-tensile spring eliminate nose-dives, ensuring continuous feeding under rapid fire.
- Aggressive Exterior Texturing: Raised side ribs and stippling provide rapid physical orientation and non-slip extraction from tactical nylon pouches.
- Integrated Over-Insertion Shoulder: Prevents over-travel into the receiver, protecting internal ejector and bolt carrier assemblies during aggressive reloads.
- Universal MPX Compatibility: Operates flawlessly across Gen 1, Gen 2, and Gen 3 MPX variants, including PCC, K, and Copperhead models.
Product Specifications
- Brand: Sig Sauer®
- Model/Series: MPX Enhanced Magazine
- MPN / SKU: 8900828
- UPC: 798681661497
- Caliber: 9x19mm Parabellum / 9mm Luger
- Capacity: 20 Rounds
- Body Material: Impact-Modified Polymer
- Feed Lip Reinforcement: Integrated Stainless Steel
- Follower: Anti-Tilt High-Lubricity Polymer
- Finish / Color: Matte Black
- Platform Compatibility: Sig Sauer MPX, MPX K, MPX PCC, MPX Copperhead (All Generations)
- Country of Origin: United States
