Gen4 4″ 9mm 5″ Lightweight M-Lok Railed Upper – With BCG & CH
Original price was: $389.99.$309.99Current price is: $309.99.
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PSA Gen4 Lightweight M-Lok Railed Upper
The Lightweight M-Lok Railed Upper is a compact 9mm upper assembly featuring a 4-inch barrel and a 5-inch free-floating handguard. Its short configuration is intended for compatible AR-style 9mm platforms, subject to all applicable federal, state, and local laws. Buyers should confirm compatibility and legal classification before acquiring or possessing this component.
The PSA Gen4 4″ 9mm 5″ Lightweight M-Lok Railed Upper uses a chrome-moly-vanadium barrel with a nitride finish. The barrel has a heavy profile, a 1:10 twist rate, a 9×19mm chamber, and 1/2×28 muzzle threading. A fluted flash can surrounds the muzzle area and is designed to direct muzzle blast and noise forward. According to the manufacturer, this device is not intended to reduce recoil, muzzle rise, or visible flash.
Receiver and Handguard
A 6061-T6 billet aluminum slick-side receiver provides the foundation for this compact upper. The absence of a forward assist contributes to its streamlined exterior. Surrounding the barrel is a 5-inch lightweight handguard with a full-length Picatinny top rail and M-Lok attachment slots.
The rail system provides mounting space for compatible sights and accessories. Any accessory should be selected according to its manufacturer’s specifications, dimensional compatibility, and intended use.
Included Components and Compatibility
This Lightweight M-Lok Railed Upper is listed with a nitride-treated 8620-steel 9mm bolt carrier group and charging handle. The bolt includes an enhanced firing pin and an external 5.56-style extractor. Because 9mm AR-pattern components are not universally interchangeable, purchasers should verify compatibility with the intended receiver, magazine system, buffer arrangement, and other components through the original manufacturer or a qualified gunsmith.
The manufacturer specifically states that reliable operation with EndoMag 9mm magazine inserts is not guaranteed. Product details and included parts can also change, so the current listing and packaging should be checked before use.
Legal and Safety Notice
A short-barreled upper may create a firearm regulated under the National Firearms Act when combined with certain lower-receiver configurations. Ownership of an upper by itself does not determine the classification of every possible configuration. Consult current ATF guidance and applicable state or local regulations before possession, transfer, or configuration.
All inspection, maintenance, and compatibility evaluation should be performed with the firearm completely unloaded and ammunition stored separately. If suitability is uncertain, consult the manufacturer or a qualified firearms professional. This Lightweight M-Lok Railed Upper should only be handled and used by legally eligible adults who follow established firearm-safety practices.
