LBE Unlimited AR-15 Mil-Spec Buffer Tube Kit — Red — (Model: MILBUFKT-RED / MILBUFKTRED, UPC: 706612407755)
Build or refresh your AR-15 with a complete, mil-spec-compatible Buffer Tube Kit from LBE Unlimited. The MILBUFKT-RED delivers everything you need to install a carbine-length stock system or replace worn buffer-assembly components — all finished in eye-catching red to add a custom touch to your rifle while retaining rugged, range-ready performance. This kit is perfect for builders, armorers, and enthusiasts who want a reliable, drop-in solution compatible with standard AR-15 receivers and most six-position carbine stocks.
Product Overview
The LBE Unlimited AR15 Mil-Spec Buffer Tube Kit bundles the critical components for the rear of your lower receiver: a mil-spec buffer tube, recoil spring, recoil buffer, castle nut, receiver/end plate, and the small hardware needed for installation. Finished in bold red, this kit makes it easy to identify your build components while offering the same function and fit demanded by mil-spec builds.
SEO keywords: AR-15 buffer tube kit, mil-spec buffer tube, carbine buffer tube kit, AR15 recoil spring, castle nut & end plate kit, red buffer tube, AR-15 stock kit.
What’s Included
Mil-Spec Buffer Tube (Carbine-Length) — Mil-spec diameter to accept standard carbine stocks and maintain proper fit with mil-spec receivers.
Recoil Spring (Buffer Spring) — Precision spring tuned for standard carbine buffer systems.
Recoil Buffer (Carbine Buffer) — Drop-in buffer designed to interface with the included spring and your bolt carrier group for reliable cycling.
Castle Nut — Secures the receiver end plate to the buffer tube with a clean, professional look.
Receiver / End Plate — Provides sling attachment point and correct spacing for the castle nut.
Buffer Retainer & Spring (where applicable) — Ensures the buffer stays retained in the tube when the receiver is separated.
Installation Hardware — Roll pins, detents, or small parts required for common drop-in installations (check kit contents on packaging).
Note: This kit is sold as a complete mil-spec-style assembly. Some aftermarket stocks and commercial-spec receiver extensions may require additional spacers or adapters; verify compatibility prior to installation.
Key Features & Benefits
Mil-Spec Compatibility: Built to standard mil-spec dimensions so the tube accepts most six-position carbine stocks and interfaces properly with mil-spec lower receivers.
Complete Assembly: Everything necessary to set up a buffer tube and stock is included — no running to the hardware store mid-build.
Durable Finish: Distinctive red finish adds a custom look while resisting corrosion and wear from regular use.
Reliable Function: Properly matched buffer and spring deliver consistent cyclic timing and dependable operation with standard bolt carrier groups and ammunition.
Easy Installation: Drop-in design for fast installation by hobbyist builders or professional armorers; basic armorer tools required.
Versatile Use: Ideal for custom builds, spare parts kits, armory maintenance, or replacing worn components after heavy use.
Compatibility & Fitment
Platform: AR-15 / .223 / 5.56 NATO lower receivers using mil-spec buffer tube dimensions.
Stock Compatibility: Most mil-spec six-position carbine stocks (verify model for non-standard or proprietary stocks).
Buffer System: Carbine-length buffer and spring intended for standard carbine gas systems — not for pistol-length or rifle-length assemblies.
Important: Always verify your receiver and stock specifications (mil vs commercial) before installation to ensure a precise fit.
Installation Quick Guide
Safety First: Clear the rifle and ensure it is unloaded. Work on a clean, stable bench.
Install Buffer Retainer & Spring: Place buffer retainer & spring into the lower and hold with a small punch while threading the buffer tube.
Thread Buffer Tube: Thread the mil-spec buffer tube into the receiver until the retainer is captured.
Install Buffer & Spring: Insert recoil spring and buffer into the tube.
Add End Plate & Castle Nut: Slide end plate and castle nut onto the tube, align sling point, and torque the castle nut to spec.
Function Check: Reassemble the rifle and perform a function check before live-fire. Adjust buffer/spring combination as needed for different BCG weights or ammo.
Tools Suggested: Armorer’s wrench, torque wrench, receiver vise block, punch set. If you prefer, have a qualified gunsmith perform installation.
Maintenance & Care
Inspect the buffer tube, spring, and buffer regularly for wear or deformation, especially after high round counts.
Keep mating surfaces clean and lightly lubricated per AR-15 maintenance best practices.
If you experience unusual cycling (hard ejection, short stroking, or over-gassing symptoms), verify spring rate and buffer weight are appropriate for your gas system and BCG weight.
Replace springs and buffers when signs of metal fatigue or loss of spring tension appear.
Ideal For
New AR-15 builders completing a carbine-length stock system
Armorers and armories stocking spare parts for maintenance and repairs
Shooters customizing rifles who want a standout red accent component
Anyone replacing a worn buffer tube assembly or upgrading from a damaged OEM part
Technical Snapshot (At-A-Glance)
Model: MILBUFKT-RED / MILBUFKTRED
UPC: 706612407755
Type: Mil-Spec AR-15 Buffer Tube Kit — Carbine Length
Includes: Buffer tube, recoil spring, recoil buffer, castle nut, receiver/end plate, buffer retainer & hardware
Finish: Red (durable tactical finish)
Compatibility: Mil-spec AR-15 lowers, six-position carbine stocks
Why Choose the LBE Unlimited MILBUFKT-RED?
The LBE Unlimited Mil-Spec Buffer Tube Kit offers the convenience of a one-box solution that doesn’t cut corners on fit or function. It’s an easy, affordable way to complete a build, refresh a worn rear-end assembly, or standardize parts across multiple rifles. The red finish provides a personal touch without sacrificing the mil-spec dimensions and performance you expect.
Final Thoughts
A small group of components plays a big role in rifle performance and ergonomics. The LBE Unlimited AR-15 Mil-Spec Buffer Tube Kit (MILBUFKT-RED) gives you the complete, mil-spec-compatible assembly needed to mount a carbine stock and ensure reliable cycling — all with an unmistakable red finish. Whether you’re finishing a first build or maintaining a fleet of rifles, this kit delivers value, compatibility, and dependable operation.
The End
