A Phase 5 Weapon Systems PBTCA buffer tube assembly for AR pistol platform builds a solid, mil-spec foundation for your AR pistol build. This complete assembly includes everything you need to properly attach and cycle your upper receiver: a billet aluminum pistol buffer tube, carbine buffer, enhanced buffer spring, Mil-Spec end plate, castle nut, and a durable foam pad. Whether you're running a Sig Sauer pistol stabilizing brace or another compatible brace, this assembly handles the mechanics so you can focus on the ergonomics and controls that matter to you.

Phase 5 engineered this kit with billet aluminum construction and precision machining to ensure reliability across builds. The lower slot is machined to accept standard Mil-Spec end plates and sling mounting accessories, giving you room to configure your pistol the way you shoot it. The black finish resists wear and looks clean, whether your AR pistol is a range workhorse or a defensive build.

If you're assembling an AR pistol or upgrading an existing platform, this buffer tube assembly takes the guesswork out of component compatibility. Everything is pre-matched and spec'd to function together—just install it, add your upper, and you're ready to shoot.

Key Features

• Complete buffer tube assembly with all essential components included
• Billet aluminum construction for durability and precision
• Mil-Spec end plate, castle nut, carbine buffer, and enhanced buffer spring
• Lower slot machined to accept standard Mil-Spec end plates and sling mounts
• Durable NPVC foam pad for comfort and grip
• Black finish
• Compatible with Sig Sauer pistol stabilizing braces and other standard AR pistol accessories

Specifications

Brand	Phase 5 Weapon Systems
Product	PBTCA Buffer Tube Assembly
Platform	AR Pistol
Material	Billet Aluminum (tube); NPVC (pad)
Finish	Black
Includes	Pistol buffer tube, carbine buffer, enhanced buffer spring, Mil-Spec end plate, castle nut, foam pad

Frequently Asked Questions

Is this buffer tube assembly compatible with a Sig Sauer pistol stabilizing brace?

Yes. Phase 5 engineered this assembly to work with Sig Sauer pistol stabilizing braces and other standard AR pistol braces that accept Mil-Spec buffer tubes.

What's included in this complete assembly?

The assembly includes a billet aluminum pistol buffer tube, Mil-Spec end plate, castle nut, carbine buffer, enhanced buffer spring, and a durable foam pad. It's a complete kit ready to install.

Can I mount a sling to this buffer tube?

Yes. The lower slot is machined to accept Mil-Spec end plates and sling mounting accessories, so you can add your preferred sling attachment.

What makes this a better choice than a basic buffer tube?

Phase 5 pairs precision billet aluminum construction with an enhanced buffer spring and quality Mil-Spec components. Everything is matched and tested as a complete system, eliminating compatibility guesswork and ensuring reliable cycling across AR pistol builds.