Magpul ACS-L Carbine Stock Mil-Spec for AR-15/M4
Mix and match across the range: 2 items save 5%, 3 save 10%, 4 or more save 15% on your whole basket.
Fits AR-15/M4 rifles with a Mil-Spec-diameter carbine receiver extension (buffer tube). Check your tube specification before ordering.
Not sure it fits your rifle? Ask us before you order
The Magpul ACS-L is a mil-spec carbine stock with onboard battery storage for AR-15 and M4 rifles, fitting any Mil-Spec-diameter receiver extension.
ACS capability on a diet — the ACS-L keeps the locked-down weld and battery storage while shedding the bulk.
The Magpul ACS-L Carbine Stock (MAG378) — Adaptable Carbine/Storage, Light — streamlines the full ACS concept for shooters who want its wobble-resistant stability and onboard battery storage without the width and weight of the flagship. The friction-lock interface still clamps the stock firm against the receiver extension for a stable, repeatable cheek weld; the storage slims down to efficient battery tubes rather than full compartments.
The slimmer housing handles faster and clears kit more cleanly, while the rubber buttpad and reinforced polymer construction carry the usual Magpul guarantees. It is the pragmatic middle path of the stock line — most of the capability, noticeably less of the mass.
Fits AR-15/M4 rifles with a Mil-Spec-diameter carbine receiver extension (buffer tube). Commercial-diameter tubes are slightly larger and will not take it, so check your tube specification before ordering — if you are not sure which you have, measure the tube or contact us with your rifle's make and model. Slide on, set length, engage the lock; battery tubes load from the rear.
| Platform | AR-15 / M4 |
|---|---|
| Fits | Mil-Spec carbine receiver extension |
| Type | Collapsible carbine stock with battery storage tubes |
| Material | Reinforced polymer |
| Finish | Black, Flat Dark Earth, Olive Drab Green |
| Adjustment | Friction lock |
| Brand | Magpul Industries |
| MPN | MAG378-BLK · MAG378-FDE · MAG378-ODG |
The lighter way to lock down. Order the ACS-L today — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: Rifle & Shotgun Stocks, Precision Rifle Stocks, AR-15 Parts or browse all Magpul.
| Platform | AR-15 / M4 |
|---|---|
| Fits | Mil-Spec carbine receiver extension |
| Type | Collapsible carbine stock with battery storage tubes |
| Material | Reinforced polymer |
| Finish | Black, Flat Dark Earth, Olive Drab Green |
| Adjustment | Friction lock |
| Brand | Magpul Industries |
| MPN | MAG378-BLK · MAG378-FDE · MAG378-ODG |
| Category | Rifle Stock |
| Shipping weight | 1.0 kg |
| Barcode | 873750006314 |
£5 tracked UK delivery on every order via Royal Mail Tracked 24. Our products are ordered in from the manufacturer rather than held in UK stock, so please allow 7 to 10 business days (Monday to Friday, excluding bank holidays) from the date of your order for it to reach you. Tracking details are emailed on dispatch. UK delivery only.
You have 30 days from receiving your order to cancel it for any reason, then 14 days to send it back unused and in its original packaging. Faulty, damaged or incorrect items are replaced or refunded and we cover reasonable return postage. Refunds go back to your original payment method within 14 days of receiving the return.
It is made for AR-15/M4 rifles with a Mil-Spec-diameter carbine receiver extension. Commercial-diameter tubes are slightly larger and will not take it, so check your tube specification before ordering. If you are not sure which you have, measure the tube or <a href="/pages/contact">contact us</a> with your rifle's make and model.
The ACS-L is the slimmer, lighter version of the ACS: it keeps battery storage but uses streamlined tubes rather than the fuller compartments of the standard stock. That gives a less bulky stock that still carries a few essentials. If storage volume matters more than profile, look at the <a href="/products/magpul-acs-carbine-ar-15-stock-mil-spec-mag370">standard ACS (MAG370)</a>.
It has battery storage tubes built into the body, sized for small items rather than bulky spares. They are closed off within the stock so contents are not rattling loose on the rifle. Check what you intend to carry will physically fit before relying on it.
Black, Flat Dark Earth and Olive Drab Green are available, all identical apart from colour. Swapping a carbine stock is usually just a matter of releasing the adjustment lever and sliding the old stock off the tube, so no special tooling is normally involved. If you are still choosing, our <a href="/blogs/buying-guides/choosing-an-ar-15-stock">AR-15 stock guide</a> compares the options.
Stocks are dispatched from the United Kingdom with £5 tracked UK delivery in 7–10 business days and tracking is emailed once the parcel is on its way. If the buffer tube diameter turns out to be wrong, see our returns policy or <a href="/pages/contact">contact us</a> and we'll help sort it.
7 to 10 business days from the date of your order. Every order is sent Royal Mail Tracked for a flat £5 and you receive tracking details by email when it is dispatched.
Yes. We list only genuine parts and optics from the brands shown, ordered in from the manufacturer for your order.
Compatibility notes on this page come from the manufacturer. If you are unsure, email us with your make and model before ordering and we will check rather than guess.
Yes. Bundle & Save applies automatically in your basket: 5% off when you buy 2 items, 10% off at 3 items and 15% off at 4 or more. It works across the whole range, so you can mix and match, and there is no code to enter.
Yes — you have 30 days from delivery to cancel for any reason, as long as the item is unused and in its original packaging. See our returns policy for the details.
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