Brownells Ar-15 Lower Reciever/Buffer Tube Vise Fixture, Black

Building or maintaining an AR-15 platform is straightforward until you're fighting a rotating buffer tube while trying to torque the castle nut—that's where the Brownells AR-15 Lower Receiver/Buffer Tube Vise Fixture steps in. This hard-coated anodized aluminum work aid clamps into your bench vise and holds your lower receiver steady while you install or service your buffer tube and castle nut. Instead of jury-rigging a solution or holding the tube by hand, you get a dedicated fixture designed by gunsmiths who've felt that same frustration.

The fixture accommodates both mil-spec and commercial buffer tubes via an adjustment screw on the sliding tube support—no need to buy different tools for different builds. Drop your lower receiver onto the fixture, thread the buffer tube through the sliding support, and tighten down. The support slides toward the receiver, leaving you enough room to work an armorer's wrench cleanly without binding or stripped fasteners. When the fixture is locked and your tube is aligned, you can confidently torque the castle nut to spec.

Compact and bench-ready, this aluminum fixture measures 7.09" long and 5.41" tall, fitting most vise configurations. Whether you're a builder assembling uppers and lowers, a gunsmith doing maintenance, or a serious shooter tweaking your own rifle, having a dedicated holding solution eliminates guesswork and frustration—and keeps your receiver and tube damage-free during service.

Key Features

• Holds both mil-spec and commercial AR-15/M4 buffer tubes
• Hard-coated anodized aluminum for durability and corrosion resistance
• Sliding tube support with adjustment screw for different tube sizes
• Clamps securely into any standard bench vise
• Keeps buffer tube aligned and stationary while tightening castle nut
• Compact footprint: 7.09" L × 5.41" H

Specifications

Frequently Asked Questions

What buffer tube sizes does this fixture support?

The Brownells fixture accommodates both mil-spec and commercial AR-15/M4 buffer tubes. The sliding tube support is adjustable via a screw on top to fit either tube diameter, so you don't need separate fixtures for different builds.

Will this work in any bench vise?

Yes—the fixture is designed to clamp into any standard bench vise. The anodized aluminum body and compact dimensions (7.09" L × 5.41" H) fit most vise jaw openings.

Can I use this for an AR-15 build from scratch?

Yes. Whether you're assembling a complete lower or servicing an existing one, the fixture keeps your receiver stable and your buffer tube from rotating while you install or tighten the castle nut to proper torque specs.

Does it include a wrench or torque tool?

The fixture is a holding tool only. You'll use your own armorer's wrench to tighten the castle nut; the fixture is designed to leave adequate room for wrench clearance once the tube support is positioned.