Out of stock
SKU: AMLLOC308GEN4N
UPC: 850006894116
MPN: LOC308GEN4N
The AR MAG LOCK Gen 4 (MPN LOC308GEN4N) is a fixed magazine lock built for narrow-width AR-10 and .308 receivers, with a shorter-length shaft to match that smaller rec width. It replaces the standard magazine release with a locking mechanism that prevents quick magazine removal, keeping a semi-automatic rifle compliant in states that require fixed magazines, including California and New York. Shooters running an Aero Precision M5, DPMS-pattern, S&W M&P, Troy, Wilson Combat, CMMG Mk3, or similar narrow .308 lower will find this version cut to fit. It installs into the lower receiver and works as a magazine release replacement.
Gen 4 adds a set screw on the locking arm so the unit adjusts to any receiver width, including billet, composite, and 80% non mil-spec lowers. Paired with the included KingPin, the design allows minimal separation of the upper and lower receivers during disassembly, and the KingPin keeps the upper from swinging open when you break the action. The lock retains full bolt catch functionality, holds the bolt back on the last round, and clears double feeds cleanly. Magazine changes stay close to the speed of a standard OEM mag button, and the safety selector remains fully accessible. Builders working through a lower parts kit can fit this alongside their existing fire control and bolt catch hardware.
Reach for this version when your .308 build sits in a state with fixed-magazine requirements and you still want the rifle to run like a service gun. The set-screw adjustment lets you switch to free-state configuration when traveling outside California, then lock it back down on return. It carries USPTO patent number 8,756,845 on the locking kit and 10,126,078 on the KingPin, and the manufacturer rates it 100% California legal and DOJ compliant. Confirm your lower is on the narrow-width list before ordering, since this short-shaft model does not fit every .308 receiver. Browse the rest of our parts catalog for matching magazine and lower components.
This short-shaft version is cut for narrow-width .308 receivers including Aero Precision M5, DPMS, S&W M&P, Troy, Wilson Combat, CMMG Mk3, LMT, JD Machine, SLR Rifleworks, Windham, Stag Arms, Ruger SR-762 .308, and Diamond Back DB10. Confirm your lower before ordering, as it does not fit every .308 receiver.
Yes. The Gen 4 retains full bolt catch functionality and holds the bolt back on the last round, just like a standard build. It also clears double feeds and allows magazine changes at close to the speed of a standard OEM magazine release button.
The KingPin works with the Gen 4 lock to allow minimal separation of the upper and lower receivers during disassembly. It holds the upper receiver from swinging open when you break the action, making cleaning and maintenance easier on a fixed-magazine setup.
Yes. Gen 4 adds a set screw on the locking arm that lets you adjust the unit, allowing a free-state configuration when traveling outside states like California. You can lock it back down when you return to a state requiring a fixed magazine.
The manufacturer rates the AR MAG LOCK Gen 4 as 100% California legal and DOJ compliant. It is designed for compliance with laws requiring fixed magazines on semi-automatic rifles, including those in California and New York. Verify current state and local law before relying on it.
WARNING ⚠️ You must be 18 or older to purchase shotgun or rifle ammunition and 21 or older to purchase handgun ammunition and firearms. Please reference our requirements for ammunition orders to "restricted" states HERE. Always make sure you use the correct ammunition for your firearms. Ammo cannot be shipped to a PO Box. Please reference state & local laws before making a firearm or ammunition purchase.
JUGGERNAUT TACTICAL INC