Image unavailable
Ar-15/M16 Buffer Tube Assembly - Mil-Spec Buffer Tube Assembly
Our editorial team reviews specifications, product data, and field-use information to keep pages accurate.
$65.99
View on Brownells
You'll be taken to Brownells to complete your purchase.
Hunter's Outpost earns a commission from affiliate links at no extra cost to you.
SKU: 080000555
Overview
This kit provides the components needed to mount a buttstock on a standard AR-15, M16, or M4-pattern lower receiver, making it a practical choice for stock replacement or a conversion to a collapsible carbine setup. The mil-spec version uses a 1.148" O.D. six-position receiver extension for proper fit with military M4 carbine buttstocks and clones. It includes installation instructions and the parts required for the assembly, with materials specified as aluminum and steel in the listed components. For buyers matching a mil-spec stock to a compatible lower, it offers a straightforward way to complete the setup without extra sourcing.
Why Hunters Choose the Brownells
Complete Kit
Includes the components needed to
Mil-spec Version
Uses a 1.148-inch O.D. six-position
Stock Conversions,
Including setups for collapsible carbine
Fits Standard,
Mil-spec AR-15/M16/M4 lower receivers and
Installation Instructions
Are included for straightforward assembly
Key Features
- Complete kit includes the components needed to mount a buttstock on an AR-15 rifle or carbine.
- Designed for stock conversions, including setups for a collapsible carbine stock.
- Mil-Spec version uses a 1.148" O.D. six-position receiver extension.
- Fits standard, mil-spec AR-15/M16/M4 lower receivers and clones.
- Receiver extension and A2 stock spacer are aluminum with a matte black anodized finish.
- Installation instructions are included.
Best Used For
- AR-15/M16 owners planning a stock conversion to a collapsible carbine setup.
- Builders needing a mil-spec receiver extension for compatible M4 carbine buttstocks.
- Users replacing or assembling buttstock mounting components on standard mil-spec lower receivers.
- Hunters configuring a rifle or carbine with included installation instructions and matched parts.
Specifications
| A2 Stock Spacer Finish | Anodized, matte black |
|---|---|
| A2 Stock Spacer Material | Aluminum |
| Compatibility | Standard, mil-spec AR-15/M16/M4 lower receiver and clones |
| Installation Instructions Included | Yes |
| Lock Ring Material | Steel |
| Receiver Extension Finish | Anodized, matte black |
| Receiver Extension Material | Aluminum |
| Receiver Extension O D | 1.148" |
| Receiver Extension Positions | Six-position |
| Receiver Extension Type | Mil-Spec |
| Receiver Plate Material | Steel |
| Recoil Buffer Material | Aluminum and steel |
| Spring Material | Steel |
Pros
- Complete kit includes the components needed to mount a buttstock on an AR-15 rifle or carbine.
- Mil-spec version uses a 1.148-inch O.D. six-position receiver extension.
- Designed for stock conversions, including setups for collapsible carbine stocks.
- Fits standard, mil-spec AR-15/M16/M4 lower receivers and compatible clones.
- Installation instructions are included for straightforward assembly.
- Brownells-manufactured kit with components held to strict dimensional tolerances.
Considerations & Trade-offs
- This is a mil-spec receiver extension kit, so it is intended for correct fit with military M4 carbine buttstocks rather than commercial or universal stocks.
- The kit is for standard, mil-spec AR-15/M16/M4 lower receivers and clones, so compatibility should be confirmed before use on nonstandard setups.
- Installation is supported by included instructions, but the product is still a conversion component and may require careful fitting during assembly.
- The kit includes the buffer tube assembly components, not a complete buttstock, so the stock itself must be selected separately.
Suggested Comparisons
- AR-15/M16 stock conversion kits
- Mil-spec receiver extensions
- Commercial-spec receiver extensions
- AR-15 lower receiver parts kits
Suggested Accessories
- AR-15/M16 buttstock
- Carbine stock
- Lower receiver parts
- Installation tools
Frequently Asked Questions
What does this buffer tube assembly kit include?
It is a convenient kit with the components needed to mount the buttstock of your choice on an AR-15 rifle or carbine. The source also notes that installation instructions are included.
Is this the mil-spec or commercial version?
This product title identifies it as the Mil-Spec Buffer Tube Assembly. The source says the mil-spec kit has a 1.148" O.D. six-position receiver extension for correct fit of military M4 carbine buttstocks.
What rifles or lowers does this kit fit?
The listed fit is standard, mil-spec AR-15/M16/M4 lower receivers and clones.
What parts and materials are specified in the kit?
The source lists the receiver extension and A2 stock spacer as aluminum with an anodized matte black finish, the recoil buffer as aluminum and steel, and the spring, lock ring, and receiver plate as steel.
Will commercial or M4 buttstocks fit this tube?
The source says M4 buttstocks and clones will not fit commercial tubes. For this product, the mil-spec receiver extension is intended for correct fit of military M4 carbine buttstocks.