Bravo Company MK2 Receiver Extension | Buffer Tube

The Bravo Company MK2 Receiver Extension is a precision engineered buffer tube built to bring true mil spec quality to your AR-15 lower. Machined from 7075-T6 aluminum and finished with MIL-A-8625F Type III Class 2 hard coat anodizing, it meets full military specification for strength, wear resistance and durability in the harshest conditions. It is also the tube the entire MK2 system is designed around.

Most carbine tubes are an afterthought bought in a bundle. This one is a deliberate engineering choice, and it changes what the rest of the lower can do.

What Sets the Bravo Company MK2 Receiver Extension Apart

Where a typical carbine tube gives you a handful of stock positions, the MK2 features eight precision machined length of pull adjustment positions. That extra granularity lets shooters of different builds and preferences find an exact fit rather than settling for the closest notch.

Length of pull is not a comfort detail. It determines how your eye lands behind the optic, how much control you have over the rifle in an awkward position and whether the stock clears your armor or your winter jacket.

The tube suits duty grade lowers, precision builds and any carbine where the shooter cares about a repeatable mount. If you build rifles that get shared between people of different sizes, the extra positions pay for themselves quickly.

Construction Highlights

• 7075-T6 aluminum machined to full mil spec standards
• MIL-A-8625F Type III Class 2 hard coat anodized finish
• Eight precision machined length of pull adjustment positions
• True mil spec diameter for snug, wobble free stock fitment
• Precisely cut internal threading for correct alignment on the lower
• Designed as the backbone of the BCM MK2 recoil mitigation system

Specifications and Compatibility Notes

Diameter is where the quality shows immediately. True mil spec sizing means compatible stocks lock up snug with none of the side to side wobble that plagues commercial spec tubes, and that solid connection is what makes a rifle feel like one object instead of two.

The internal threading is precisely cut to guarantee proper alignment and reliable installation on your lower receiver. Correct threads keep the tube square, protect the buffer retainer and let the castle nut torque down evenly.

Plan the parts list around the Bravo Company MK2 Receiver Extension rather than adapting it afterward. The tube, the buffer and the rifle length spring form one designed assembly, and substituting a component defeats the purpose of buying it.

One important compatibility note before you order: this extension is designed to be used exclusively with the BCM MK2 buffer and a rifle length M16 action spring. Plan the build around that combination rather than dropping in standard carbine internals, and browse our bolt carriers and internals category to line up the matching pieces.

Installation, Setup and Care

Assembly follows the usual sequence. Slide the castle nut and receiver end plate onto the tube, thread the tube into the lower until it correctly captures the buffer retainer and its spring, square the end plate, then torque and stake the castle nut so recoil cannot walk it loose.

Load the correct rifle length action spring and the MK2 buffer, then hand cycle the action several times before live fire. You are checking for full carrier travel, clean bolt lockup and a retainer that holds the buffer face securely.

Set your length of pull deliberately once everything is assembled. Build a firing grip, shoulder the rifle and check that your eye lands centered behind the optic, then note which position gets you there.

Long term maintenance amounts to keeping the interior dry and free of grit. Do not oil the inside of the tube, since lubricant in there only traps carbon and dust that end up on the buffer. Wipe the exterior during routine cleaning, recheck the castle nut staking after the first outing, and inspect the stock lock lever engagement occasionally to make sure it is dropping fully into each position.

For shooters who sweat the details of a duty grade lower, the Bravo Company MK2 Receiver Extension is the tube to spec. Ships direct to your door, no FFL required.