A Proper 7075-T6 Mil-Spec Carbine Receiver Extension
The Aero Precision APRH100136C Carbine Receiver Extension is a straightforward six-position buffer tube for builders who want a conventional Mil-Spec-dimension recoil system built around quality material rather than a bargain-grade commercial tube.
Manufactured from 7075-T6 aluminum, this receiver extension provides the foundation for a conventional adjustable-stock AR carbine recoil system. It accepts compatible Mil-Spec-dimension collapsible stocks and works with the appropriate carbine buffer, carbine action spring, castle nut and receiver end plate.
Aero Precision lists this tube for AR15 and compatible AR10-pattern applications. As with all large-frame AR builds, the receiver extension itself is only one part of the recoil system; the buffer and spring must match the specific platform and operating configuration.
Why 7075-T6 Matters
Receiver extensions are available in several materials, with 6061 and 7075 aluminum among the most common. Aero uses 7075-T6 for this tube, providing greater strength than the lower-strength aluminum commonly encountered in inexpensive commercial receiver extensions.
That matters because the receiver extension is more than something for the stock to slide over. It threads directly into the lower receiver, contains the buffer and action spring, absorbs repeated recoil-system loads and provides the structural connection between the rifle and an adjustable stock.
On a component performing all of those jobs, starting with the stronger alloy is a sensible choice.
Six Stock Positions
The bottom rail incorporates six stock-position detents, allowing a compatible Mil-Spec adjustable stock to be set for different lengths of pull.
That makes it suitable for general-purpose carbines where the stock may need to accommodate different shooters, clothing layers, body armor or simply different shooting positions.
Stock-position count should not be confused with buffer-system length. This is a carbine-length receiver extension; the six positions refer to the external stock adjustments.
Mil-Spec Dimensions
This tube uses Mil-Spec receiver-extension dimensions and is intended for compatible Mil-Spec-sized carbine stocks. It should not be confused with the larger-diameter commercial-spec receiver extensions found on some older or lower-cost AR configurations.
When replacing an existing tube, verify the stock is designed for a Mil-Spec-diameter receiver extension before assuming the two components will fit together.
AR15 and Large-Frame AR Compatibility
On a conventional AR15, this receiver extension is used with an appropriate carbine buffer and carbine action spring.
It can also be used in many AR10 / .308-pattern configurations, but large-frame AR recoil systems are not standardized to the same degree as the AR15. Depending on the rifle, a shorter .308-specific carbine buffer, different spring or other platform-specific component may be required.
Do not assume that an AR15 carbine buffer can simply be transferred into every .308 AR merely because the same receiver extension is used. Verify the buffer and spring requirements for the specific large-frame receiver and bolt-carrier system.
Receiver Extension Only
This listing is for the receiver extension / buffer tube only. A buffer, action spring, receiver end plate, castle nut and stock are not included unless specifically stated otherwise.
That makes APRH100136C useful for a fresh lower build, replacing a damaged or commercial-spec tube, or assembling a recoil system around individually selected components rather than purchasing a complete buffer kit.
Build the Recoil System Around the Application
The receiver extension establishes the physical space in which the carbine buffer and action spring operate, but buffer weight and spring selection are what allow the builder to tune the system to the firearm.
A standard carbine buffer is a conventional baseline for many AR15 builds, while heavier H, H2 and H3 buffers can be appropriate depending on gas-system configuration, ammunition, suppressor use and operating requirements.
The important point is that the tube does not dictate one universal buffer weight. It gives the builder a quality Mil-Spec foundation around which the rest of the carbine recoil system can be selected.
Made in the USA
Aero Precision manufactures AR components in the United States and identifies this receiver extension as American made. Aero-branded carbine extensions are also specifically identified by Aero as compatible with Mil-Spec carbine stocks such as Magpul's PRS Gen3 where applicable.
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