MOE M4 Military Model Carbine Replacement Butt Stock Mil-Spec - Black - Magpul


Item #: MPMAG400


In Stock for Immediate Shipping

Manufacturer MPN:
Magpul MAG400

UPC: 873750003108
Weight: 0.85 pounds

Product Description

MOE Carbine Stock – Mil-Spec

Made in the USA

Platform: AR10, AR15, M4, M16, M110, SR25
Compatibility: Mil-Spec sized carbine receiver extension tube (not included) from manufacturers such as Colt, LMT, Ruger, S&W, SIG, and others.
LOP, M4 Collapsed: ~ 10.5”
LOP, M4 Extended: ~ 13.8”
LOP Adjustment Range: 3.3”
Length, Max: 6.9”
Weight: 8.0 oz.
Weight, w/ Receiver Extension: 12.0 oz.

Dependable AR Stock
Secure Fit
The Right Balance of Cheek Weld and Comfort
Set it and Forget It
Sling Point Options
Impact Mitigation

Magpul Original Equipment (MOE) is a line of firearm accessories designed to provide a high-quality, economical alternative to standard weapon parts. The MOE line distinguishes itself with a simplified feature set but maintains Magpul engineering and material quality.

The Magpul MOE Carbine Stock – Mil-Spec is a drop-in replacement buttstock for AR15/M16 carbines using mil-spec receiver extension tubes.

Designed for light, fast action the streamlined A-frame profile avoids snagging and shields the release latch to prevent accidental activation.

The Mil-Spec Model includes a standard 0.30" rubber butt-pad which provides positive shoulder purchase to prevent slippage and increases impact protection, even with body armor or modular gear.

Mounts on Mil-Spec sized carbine receiver extension tube. Premium chrome-silicon lock spring provides positive locking and long service life. Sloping cheek weld combined with a slim profile with user comfort. Side mounting slots accept optional cheek risers for NON AR15/M4 applications. Shielded release latch prevents snagging and accidental operation.

Sling Point Options

Compatible with Magpul ASAP, ASAP QD, and other receiver-mount sling attachments.

Rear/Bottom – 1.25” sling loops
Toe – Lanyard hole for custom para-cord rigs

Specifications based on standard-length (flat-back) M4 Carbine Receiver Extension and may vary depending on tube manufacturer.


MOE Carbine Stock Installation Instructions

Step 1:  Remove Existing Stock

Remove existing stock per armory guidelines. Refer to US Army TM 9-1005-319-23&P for assistance.

Step 2: Install CTR Stock

DO NOT FORCE PARTS TOGETHER!! Align the stock body with the carbine receiver extension and gently slide together until the stock stops (approx. 2-1/8”). Depress release latch with one hand. With the other hand, grasp both ends of release pin and pull down firmly. Push stock forward to mount.

NOTE: If stock does not easily slide over receiver extension, refer to fit guide on box.

Step 3: Verify Install

Perform final inspection including function test per US Army TM 9-1005-319-23&P Unit and Direct Support Maintenance Manual to verify correct installation. If you experience any issues during installation, please refer to the “Related Info” tab, located on the product page at Always test fire your weapon before using it in an operational environment.

Removing MOE Stock

Depress release latch with one hand. With the other hand grasp both ends of the release pin and pull down firmly. Pull the stock body clear of the carbine receiver extension.

MOE Carbine Stock Adjustment Instructions

Extend/Collapse Stock

Fully depress the release latch and pull the stock rearward to extend or push stock forward to collapse. Intermediate positions may be selected by depressing the release latch and moving the stock back to the desired position. When desired position is found re-engage friction lock bolt for best results.

Remove Rubber Butt Pad

Use a 1/8” hex key to remove the two butt pad screws. Using a bullet tip or flat head screwdriver, depress the two top snap hooks to release the pad. Install optional polymer Carbine Butt Cap if desired.


WARNING: The CTR commercial model has an extended .55” rubber butt pad to accommodate extended-length receiver extensions (buffer tubes). Removal of the butt pad is not recommended since the extension tube may protrude past the end of the stock in the fully collapsed position and may cause discomfort or injury during use.

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