LBE Unlimited Mil-Spec Buffer Tube Kit — AR-15, 6-Position, Black
Model: MILBUFKT • UPC: 765857617480 • Fits: AR-15 / M4-pattern lowers • Includes: Buffer Tube, Castle Nut, Lock Plate (End Plate)
Upgrade or complete your AR-15 build with the LBE Unlimited Mil-Spec Buffer Tube Kit (MILBUFKT)—a dependable, no-nonsense receiver extension assembly that delivers correct Mil-Spec diameter, 6-position adjustability, and rock-solid retention. Whether you’re refreshing a duty carbine, piecing together a lightweight build, or standardizing parts across a fleet, this kit gives you the essentials you need for a secure, repeatable stock interface—without the guesswork.
Why Choose the LBE Unlimited MILBUFKT
True Mil-Spec Diameter: Built to the standard ~1.148" receiver extension size for broad compatibility with Mil-Spec adjustable stocks (not commercial-spec).
6-Position Adjustability: Fine-tune length of pull for armor, layers, or different shooters—critical for control and comfort.
Complete Mounting Hardware: Comes with the castle nut and lock plate (end plate) you need for a proper installation and staking.
Reliable Fit & Finish: Uniform threads and a durable black finish support smooth assembly and long service life.
AR-15 Platform Ready: Sized for standard AR-15/M4 lowers and common carbine-length recoil systems.
Note: This kit includes the buffer tube, castle nut, and lock plate. Buffer and recoil spring are not included unless specified by your retailer—choose your preferred weight/spring combo to match your gas system and use case.
Key Features
Mil-Spec Receiver Extension: Ensures compatibility with most Mil-Spec collapsible stocks from leading brands.
Precision Threading: Clean, consistent threads help prevent cross-threading and ease installation.
Secure Retention: The included castle nut locks the extension in place; the lock plate captures the takedown detent spring and sets you up for proper staking.
Durable Black Finish: Resists wear and blends seamlessly with modern AR components.
Builder-Friendly: A straightforward kit for new builds, refurbishments, or spare-parts bins.
Technical Specifications
Brand: LBE Unlimited
Model: MILBUFKT
UPC: 765857617480
Platform: AR-15 / M4 (carbine-length recoil system)
Tube Diameter: Mil-Spec (~1.148")
Positions: 6
Color/Finish: Black
Included Parts: Buffer Tube, Castle Nut, Lock Plate (End Plate)
Not Included: Buffer, recoil spring, stock, takedown detent/spring, buffer retainer/spring
Compatibility & Use Cases
AR-15 Carbines & Pistols (where legal): Standard carbine receiver extension footprint for adjustable stocks.
Duty/Defense, Range, Competition: Set your length of pull for body armor, prone stability, or CQB maneuverability.
Fleet Standardization: Keep spares on hand to simplify maintenance and armorer workflows.
Installation Overview (Best Practices)
Prep the Lower: Verify the firearm is unloaded. Remove the old receiver extension if present.
Install Buffer Retainer & Spring: Start threading the buffer tube until it retains—but does not crush—the buffer retainer (parts not included).
Capture the Takedown Spring: Slide the lock plate to capture the rear takedown detent spring; run the castle nut up to the plate.
Align & Torque: Square the tube to the lower. Torque the castle nut to commonly referenced carbine spec (~38–40 ft-lbs).
Stake the Castle Nut: Displace a small amount of lock-plate metal into the castle nut’s notch for duty-grade security.
Function Check: Ensure the takedown pin, buffer retainer, and stock lockup operate correctly.
If you’re not experienced with AR assembly, a qualified armorer can install and stake the extension quickly and safely.
Tuning Tips
Buffer Weight: Choose standard carbine, H, H2/H3, or a tuned buffer to match your gas length, port size, and ammo.
Spring Choice: Pair with a quality carbine recoil spring for consistent lock-back and ejection.
Stock Selection: Use Mil-Spec pattern stocks for the best fit—commercial-spec stocks will be loose.
Care & Maintenance
Periodically confirm castle nut staking and tightness after high round counts or temperature swings.
Keep threads lightly lubricated during assembly; avoid over-torque.
Inspect the receiver extension for dents or damage after hard use; replace if compromised.
SEO-Optimized Keywords & Phrases
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Short Meta Description
LBE Unlimited MILBUFKT Mil-Spec Buffer Tube Kit for AR-15—includes buffer tube, castle nut, and lock plate, 6-position Mil-Spec diameter for adjustable stocks. UPC: 765857617480.
Buyer’s Quick Checklist
✅ AR-15 lower with carbine-length recoil system
✅ Want Mil-Spec diameter for broad stock compatibility
✅ Need 6-position adjustability
✅ Comfortable selecting your own buffer & spring (not included)
Build smarter and lock down a dependable stock interface with the LBE Unlimited Mil-Spec Buffer Tube Kit (MILBUFKT)—the streamlined foundation your AR-15 deserves.
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