The LBE Unlimited Mil-Spec 6-Position Buffer Tube Kit in black (brand part no. MILBUFKT) is a complete rear-end package for an AR-15 or M4-style build. LBE Unlimited pairs a six-position mil-spec buffer tube with a carbine recoil spring, a carbine recoil buffer, a receiver end plate and a castle nut, so the lower is ready for a stock without hunting for individual parts. The tube is made to military dimensions and accepts standard mil-spec AR-15 buttstocks, and the spring and buffer are tuned for standard 5.56/.223 setups. It suits a new rifle or pistol build, a mil-spec upgrade over a commercial-spec kit, or a spare set for field repairs.

Key Specifications

• The buffer tube is a six-position, mil-spec diameter receiver extension, which accepts standard mil-spec AR-15 buttstocks and gives six length-of-pull settings.
• A carbine recoil spring is included, so the buffer assembly does not need a separate spring purchase.
• A carbine recoil buffer is included and matched to the spring for consistent recoil control and reliable bolt operation.
• The kit adds a receiver end plate, one of the components that finishes the rear of the lower receiver.
• A castle nut is included, so the tube can be installed without sourcing the nut separately.
• The spring and buffer are tuned for standard 5.56/.223 setups, the configuration most AR-15 and M4-pattern builds use.
• The kit is made in the USA, built to military specifications for dependable long-term use.

Frequently Asked Questions

What is included in the LBE Unlimited buffer tube kit? The kit contains a six-position mil-spec buffer tube, a carbine recoil spring, a carbine recoil buffer, a receiver end plate and a castle nut, which covers the rear of the lower receiver.

Will it accept a mil-spec buttstock? Yes. The tube is manufactured to military dimensions and accepts standard mil-spec AR-15 buttstocks, with six locking positions for length-of-pull adjustment.

What builds is this kit meant for? LBE Unlimited lists it for new AR-15 and M4 rifle or pistol builds, mil-spec upgrades over commercial-spec kits, and spare parts or field repair kits.

Buy the LBE Unlimited Mil-Spec 6-Position Buffer Tube Kit, Black

Sourcing a tube, spring, buffer, end plate and castle nut separately means more orders and more chances for a mismatch. This black LBE kit puts the full set in one box, in true mil-spec dimensions, and it is made in the USA. Browse more AR buffer system parts while you are here, then order from our Lubbock, Texas gun shop for fast shipping.