Magpul ACS Carbine Stock MAG370-FDE for AR-15/M16/M4 - Flat Dark Earth, Mil-Spec (Tube Not Included)

The Magpul ACS Carbine Stock in Flat Dark Earth is a mil-spec AR-15/M4 replacement stock that transforms a standard buffer tube into a capable, organized platform. Built for shooters and operators who want more from their stock than a simple cheekrest, the ACS combines practical storage, ergonomic design, and proven Magpul reliability in a package that stays low-profile and snag-free. Whether you're running a duty rifle, competition gun, or hunting carbine, this is the stock for people who carry spare batteries, cleaning gear, or other essentials on the gun itself.

Storage is the ACS's defining trait. A full-length removable battery compartment runs along the extra-wide comb and holds either two AA or three CR-123 batteries—common power for modern optics and lights. A secondary trapdoor on the right side opens to a roomy storage cavity for additional batteries, coiled cleaning cable, ear plugs, small spare parts, or anything else you need quick access to without opening a bag. Molded rubber caps seal each compartment and face rearward for one-handed removal; the caps are beveled to shed snags when you're moving fast or transitioning in and out of vehicles. A sling attachment point molded into the toe accepts a 1.25-inch sling, keeping your carry setup integrated.

The cheekweld is wide and contoured for a solid, repeatable sight picture—critical for any optic-mounted rifle. Magpul's dual-locking lever system adds a secondary cam lever that guards the release lever from accidental collapse during hard use, yet adjustment remains simple: just push the primary lever to change length of pull. The exterior is smooth and streamlined throughout, designed to shed vegetation and cloth without hanging up. A detachable rubber buttpad, borrowed from Magpul's CTR and UBR designs, locks the stock firmly to your shoulder and can be swapped if needed. This is mil-spec, fitting any 1.14-inch O.D. buffer tube on standard Colt-pattern and mil-spec builds.

Note: Stock only. Buffer tube not included.

Key Features

• Full-length removable battery storage compartment holds 2 AA or 3 CR-123 batteries
• Secondary trapdoor storage cavity for batteries, cleaning cable, spare parts, and small items
• Sealed rubber caps resist water and dust ingress
• Extra-wide, contoured comb for reliable cheekweld and optics support
• Dual-locking lever system prevents accidental collapse while maintaining easy length-of-pull adjustment
• Smooth, snag-resistant exterior contours for fast movement and vehicle transitions
• Molded 1.25-inch sling attachment point on toe
• Detachable rubber buttpad for shoulder control
• Mil-spec construction fits standard 1.14" O.D. buffer tubes

Specifications

Frequently Asked Questions

What buffer tube does this stock fit?

The ACS is mil-spec and fits any standard 1.14-inch O.D. buffer tube, including Colt-pattern and mil-spec tubes on AR-15, M16, and M4 carbines. The buffer tube is sold separately.

How much can I store in the battery compartments?

The primary compartment running the length of the comb holds either 2 AA batteries or 3 CR-123 batteries. The secondary trapdoor compartment on the right side accommodates additional batteries, coiled cleaning cable, spare parts, ear plugs, or other small items. Both seal with removable rubber caps.

Will this stock interfere with my sling or gear?

No. The ACS exterior is designed with smooth, streamlined contours and beveled cap edges to prevent snagging on clothing, slings, or vegetation. It won't catch when moving through tight spaces or transitioning in and out of vehicles.

Is the cheekweld height suitable for modern optics?

Yes. The ACS features an extra-wide, contoured comb designed to provide a solid, repeatable cheekweld for mounted optics and sights.