LBE Unlimited H1 Heavy Recoil Buffer Tube Kit 6-Position Mil-Spec - Black - H1BUFKT - UPC: 706612408097
Product Description
The LBE Unlimited H1BUFKT is a complete 6-position mil-spec buffer tube assembly tuned with an H1 heavy recoil buffer for AR-15 carbines, short-barrel rifles (SBRs), and suppressive firearm setups. Engineered as a comprehensive rear lower receiver staging solution, this kit equips armorers and custom rifle builders with all necessary extension hardware—including a 6-position mil-spec receiver extension, carbine action spring, H1 buffer, steel castle nut, and receiver end plate.
At the center of the kit is an H1 heavy recoil buffer (weighing approximately 3.8 oz) featuring a tungsten and steel weight configuration. The added mass slows bolt carrier velocity during the unlocking cycle, increasing dwell time, mitigating carrier bounce, and smoothing out felt recoil. This heavier inertia is particularly beneficial for over-gassed carbine gas systems, 11.5" to 14.5" barrels, and suppressed configurations where excess backpressure accelerates cycling speeds.
The 6-position buffer tube is machined from high-strength 7075-T6 aluminum and finished in a matte black hardcoat anodize for high wear and corrosion resistance. Standard mil-spec outer dimensions ensure broad compatibility with collapsible stock designs. Included in the kit are a heat-treated carbine recoil spring, mil-spec receiver end plate, and castle nut designed for proper torque application and staking.
*Armorer Bench Notes & Real-World Staging Guidance:
Gas System & Buffer Tuning Matrix:
• Primary Application: 10.5" to 16" carbine-length gas systems, 5.56 NATO / .223 Rem, .300 Blackout, and suppressed carbines.
• Stock Fitment: Mil-spec diameter 6-position tube (accepts standard mil-spec collapsible stocks).
Lower Receiver Assembly Steps:
1. Lightly lubricate the external threads of the buffer tube and the interior bore before installation.
2. Thread the castle nut and end plate onto the tube, then thread the tube into the lower receiver until it captures the rear takedown pin detent and spring.
3. Depress the buffer retainer and spring into the receiver pocket and seat the front lip of the buffer tube over the edge of the retainer pin.
4. Torque the castle nut to 38-40 ft-lbs using a dedicated armorers wrench and stake the end plate twice into the castle nut notches using a automatic center punch.
Key Features
- Complete drop-in rear lower receiver extension assembly for AR-15 platforms.
- Includes H1 heavy recoil buffer (~3.8 oz) to delay unlocking and smooth cycling forces.
- 6-position mil-spec receiver extension tube crafted from 7075-T6 aluminum.
- Matte black hardcoat anodized finish offers low glare and abrasion protection.
- High-tensile carbine recoil spring ensures consistent forward bolt carrier energy.
- Includes steel receiver end plate and castle nut for secure installation and staking.
- Proudly manufactured in the USA by LBE Unlimited.
Product Specifications
- Brand: LBE Unlimited
- MPN / Model: H1BUFKT
- UPC: 706612408097
- Tube Type: 6-Position Mil-Spec Diameter
- Tube Material: 7075-T6 Hard-Anodized Aluminum
- Buffer Weight: H1 Heavy (~3.8 oz)
- Spring Type: Carbine Length Recoil Spring
- Hardware Included: Buffer Tube, H1 Buffer, Recoil Spring, End Plate, Castle Nut
- Platform Fitment: AR-15 / M4 Lower Receivers
