Premium Fire/Safe Marked Billet 80% Lower Assembly – Complete Build Kit

You’re looking at the kit that fixes the problems other 80% lowers give you. This isn’t just a piece of aluminum; it’s a complete starting point for a solid, no-headache AR-15 build. We took a premium 7075-T6 billet lower, listened to what builders actually complain about, and machined in the solutions. Then, we bundled it with everything you need to get it running except the drill press and the finishing kit. This is how you start a build right.

What You Get in This Kit:

• 1x Premium Billet 80% Lower Receiver – Fire/Safe engraved, Mil-Spec Black anodized.
• 1x Lower Parts Kit (LPK) – All springs, detents, and fire control components.
• 1x Butt Stock
• 1x Buffer Tube Assembly – Includes buffer and spring.
• All Necessary Screws & Hex Key – For the upgraded threaded features.

This Is a Real Billet Lower. Here’s the Difference.

This lower starts as a solid block of 7075-T6 aluminum—the same stuff used in aircraft and military gear. We machine it down, unlike forged receivers which are hammered into shape. The result? Cleaner, sharper lines, a noticeably more rigid feel, and a foundation for your rifle that has virtually zero flex. The magwell is professionally broached for smooth, reliable magazine changes every time. It’s a mark of quality you can see and feel.

Engineered to Save Your Sanity (and Your Punches).

We’ve all been there: trying to tap in a roll pin for the bolt catch, sweating, hoping you don’t mar the finish or launch a detent into another dimension. We fixed that.

This lower has two key upgrades:

• Threaded Bolt Catch Release Pin Hole: No more roll pin. You install a small screw with the included hex key. It’s secure, it’s clean, and it takes 30 seconds.
• Threaded Rear Takedown Pin Detent Hole: This is the big one. You thread in a plug after the spring and detent are already in place. This completely eliminates the infamous “detent launch” during final assembly. It’s a game-saving feature.

These aren’t gimmicks. They are practical machining improvements that make the build process smoother and more professional.

The Complete Package for a Functional Lower Assembly.

We didn’t just give you the lower. We included a quality lower parts kit, a stock, and a buffer tube assembly. This means once you complete the machining of your 80% lower (which involves drilling the fire control group pocket and pin holes), you have every other component on hand to assemble a fully functional lower receiver. You won’t be stuck waiting on a separate order for your buffer kit to finish the job. It’s all here.

Clear, Legally Compliant Fire/Safe Markings.

The receiver comes with deeply laser-engraved “FIRE” and “SAFE” markings. They’re clear, permanent, and professionally done. This isn’t a sticker or a light etch; it’s a proper, lasting marking that meets expectations for a finished firearm.

100% American Made. No FFL Required for Purchase.

This lower is manufactured from start to finish right here in the United States. Because it is an 80% lower receiver (it is not considered a firearm by the ATF), it ships directly to your door with NO FFL TRANSFER required. You are the manufacturer once you complete the machining process in accordance with all federal, state, and local laws.

Important Legal Note: It is your responsibility to understand and comply with all laws regarding the manufacture and possession of firearms in your jurisdiction before purchasing. This product is intended for qualified individuals building legal, personal-use firearms.

Who This Kit Is For:

This kit is for the builder who is tired of fighting with cheap, out-of-spec lowers. It’s for the guy who appreciates the strength of billet aluminum and wants the smart upgrades that make assembly a breeze. If you want a complete package that delivers a professional result without the typical headaches, this is your lower. Stop piecing together parts from different vendors. Get the Premium Billet 80% Lower Assembly from Polymer80Deals.com and build it better.

Price: $148.49

SKU: [Your SKU Here] | Categories: 80 Percent Lower, AR-15 Parts, Build Kits