Give your AR-15 a true rifle-length upgrade with the Colt AR-15 A4 Stowage Stock Assembly Fixed OEM Black (SP64571)—the same classic fixed stock profile trusted for decades on Colt AR-15 and M16 series rifles. This is a factory Colt OEM part, built to military-style specs and designed to deliver rock-solid stability, authentic ergonomics, and internal storage in a durable polymer package. AmmoMart+2Crow Wholesale+2
Authentic Colt OEM A4 Rifle Stock
If you’re finishing a clone build, replacing a worn buttstock, or converting from a collapsible carbine stock to a full rifle-length setup, going genuine Colt matters. This A4 stowage stock assembly is manufactured by Colt and listed across distributors under manufacturer SKU SP64571, so you’re getting the real thing—not a generic copy. AmmoMart+2Crow Wholesale+2
Because it’s an OEM part, the fit and finish match Colt lowers and rifle-length receiver extensions used on AR-15, AR-15/M4, and M16-pattern rifles. AmmoMart+2GunSpot+2
Fixed Rifle-Length A4 Design for Maximum Stability
The fixed A4/A2 rifle-length configuration offers a longer length of pull and a more stable shoulder weld than compact collapsible stocks. That makes it a popular choice for:
Brownells notes that this stock assembly is compatible with a wide range of Colt rifle models including AR-15 Accurized HBAR, various Match Target rifles, and AR-15A3 Tactical Carbine when used with a rifle-length receiver extension. Brownells Schweiz
Integrated Stowage Compartment
As the name suggests, the A4 Stowage Stock includes a trapdoor buttplate with internal storage—ideal for keeping small essentials on the rifle where you need them:
Product copy from Colt distributors highlights this built-in storage as a key feature for enhanced functionality on AR-15 and M16 platforms. TheGunZone+2Blackstone Shooting Sports+2
Note: Some retailers and Brownells customer reviews mention that the buttcap spacer and upper stock screw are not included in the assembly as shipped. Brownells Österreich+1 Always check the specific seller’s contents list so you can source any additional hardware (spacer, screw, receiver extension, buffer, spring) if needed.
Durable Black Polymer Construction
The Colt AR-15 A4 Stowage Stock Assembly uses a tough polymer body finished in black, designed to stand up to hard use in the field or on the range. AmmoMart+2Frisco Guns+2
This polymer construction keeps weight manageable while still providing the solid, non-flexing feel that rifle-length stocks are known for.
Easy OEM-Style Installation
Because this is a Colt OEM rifle stock assembly, installation on a compatible lower is straightforward when you have the correct rifle-length extension components:
Uses a rifle-length receiver extension (buffer tube) and rifle buffer/spring (not included)
Installs with standard A2/A4 buttstock hardware (spacer and long stock screw—often sold separately) Brownells Österreich+1
Designed to line up with Colt-spec AR-15 and M16 lowers without fitting on most builds AmmoMart+1
Always follow standard AR-15 armorer procedures and torque guidelines when swapping stocks, and ensure your rifle is unloaded and safe before starting any work.
Ideal For:
Colt AR-15/M16 clone builds (M16A2/M16A3/M16A4 style rifles) – SP64571 is the same part used on military-style fixed rifle stocks. Specialized Armament+1
Shooters wanting a fixed, non-collapsing stock for consistency and stability
Upgrading from a generic or worn-out buttstock to a factory Colt replacement
AR owners who want on-board storage in a classic A4 stock profile
Key Features – Colt AR-15 A4 Stowage Stock Assy Fixed OEM BLK (SP64571)
Tech Specs (At a Glance)
Brand: Colt
Product Name: AR-15 A4 Stowage Stock Assembly Fixed OEM Black
Manufacturer Part #: SP64571
Style: Fixed, rifle-length A4/A2 buttstock
Color: Black
Material: Polymer / composite
Type: OEM replacement stock
Compatible Platforms: Colt AR-15, AR-15/M4, M16 (rifle-length extension) AmmoMart+2GunSpot+2
Included: Stock body with stowage buttplate (trapdoor); other receiver extension parts may be sold separately depending on retailer Brownells Österreich+1
With its combination of authentic Colt quality, classic A4 styling, and practical internal storage, the Colt AR-15 A4 Stowage Stock Assy Fixed OEM BLK (SP64571) is a go-to choice for anyone building or refreshing a rifle-length AR-15 or M16-style platform.
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