Armaspec Gun Builder's Lower Parts Kit (Excludes Fire Control Group) – Premium Quality Components for Custom AR-15 Builds

Building a custom AR-15 from the ground up? The Armaspec Gun Builder's Lower Parts Kit strips away the guesswork and gives you the small-parts foundation you need—minus the fire control group, so you can choose your own trigger and hammer to match your shooting style. If you're already committed to selecting a premium trigger or have a specific disconnect/hammer combo in mind, this kit gets you the rest of the stainless steel components that keep an AR lower running reliably, without paying for redundant parts you won't use.

Armaspec engineered this builder's kit around their own proven components. You get their SFT 45/90 safety selector, enhanced take-down pins, anti-walk trigger and hammer pins (with hex keys included), and all the detents and springs that govern the lower's function. Every part that goes in the kit is stainless steel where it matters—corrosion resistance for long-term reliability, whether you're a precision rifle builder or a tactical shooter. This is not a complete lower parts kit; it's designed for builders who know exactly what they want in a fire control group and already have one sourced.

Made in the USA and backed by Armaspec's lifetime warranty, this kit rewards builders who think through their parts choices instead of grabbing whatever's bundled together. You'll know where every component came from and trust it was made to last.

Key Features

• Armaspec SFT 45/90 safety selector for smooth, positive engagement
• Enhanced take-down pins and anti-walk trigger/hammer pins with included hex keys
• Stainless steel construction on detents, springs, and critical wear surfaces
• Bolt catch, magazine catch, and selector components all included
• Designed for .223/5.56 AR-15 lowers
• Made in the USA with lifetime warranty

Specifications

Frequently Asked Questions

What's NOT included in this Armaspec lower parts kit?

This kit excludes the fire control group—that means no trigger, hammer, trigger spring, hammer spring, disconnect, or disconnect spring. It also doesn't include a pistol grip, grip screw, grip washer, or trigger guard and its roll pin. You need to source those separately or use components you already own.

What AR-15 lower will this fit?

The kit is designed for standard AR-15 lower receivers chambered in .223/5.56. It will not fit other caliber platforms or non-standard receivers.

Why choose a builder's kit instead of a complete lower parts kit?

A builder's kit is ideal if you already own a fire control group you want to use, or if you're sourcing premium trigger and hammer components separately. You avoid paying for parts you won't install and maintain tighter control over your build's final specifications.

Does this kit include everything else I need to assemble a lower?

It includes all the small springs, detents, selector components, take-down pins, bolt catch parts, magazine catch assembly, and safety selector. You'll also get hex keys for the anti-walk pins. You'll still need to source a fire control group (trigger, hammer, springs, disconnect) and a pistol grip assembly separately.