The Magpul ACS-L Stock (brand part no. MAG378-BLK) is a drop-in replacement buttstock built for AR-15/M4 carbines running mil-spec-sized receiver extension tubes, finished in black. The ACS-L, short for Adaptable Carbine Stock – Light, streamlines Magpul’s original ACS design by removing the battery storage tubes, which trims both weight and bulk while keeping the same center storage compartment and cheek weld the original ACS is known for. That combination of a lighter shell and a still-functional storage compartment makes it a popular middle ground between a bare minimalist stock and a fully loaded one. It installs as a standard drop-in on any mil-spec buffer tube, with no special tools or gunsmithing required.

Key Specifications

• Collapsible stock fits mil-spec-sized receiver extension tubes.
• ACS-L design removes the original ACS’s battery tubes for a lighter, slimmer package.
• Retains the ACS’s center storage compartment and cheek weld.
• Finished in black.
• Direct drop-in replacement, no gunsmithing required.

Frequently Asked Questions

How does the ACS-L differ from the standard ACS? It removes the battery storage tubes for a lighter, slimmer stock while keeping the same center compartment and cheek weld.

What buffer tube does this require? A mil-spec-sized receiver extension tube.

Buy the Magpul ACS-L Carbine Stock

Get the ACS feel in a lighter, streamlined package. Order this Magpul Industries stock from our AR stock selection, and our Lubbock, Texas team will get it ready to ship as soon as it’s available.