Polymer80Buy.com Exclusive: AR-9 80% Billet Lower Receiver – 9mm, Fire/Safe Marked

Our Price: $93.49

Build a solid 9mm AR pistol or carbine right. Start with a proper billet lower.

This isn’t a flimsy starter kit. This is a 6061-T6 billet aluminum AR-9 lower, CNC-machined right here in the USA to give your build a foundation that lasts. We mill it from solid block, not extruded, for superior strength and a clean, precise fit with your upper receiver.

It’s marked “FIRE” and “SAFE” where it should be. No guessing, no extra engraving work for you. Just a ready-to-finish 80% lower that respects the process.

Built for Function, Not Just Looks

• Runs Glock Mags: Designed from the ground up for reliable feeding with Glock® OEM and ETS magazines. The platform standard for a reason.
• Flared Magwell: We enlarged the ramps. Reloads are faster and more positive, especially under pressure.
• Type III Hardcoat Anodized: This is a tough, wear-resistant finish. It’s not paint. It protects the metal and holds up to hard use.
• 100% Mil-Spec Fitment: Takes standard AR-15 lower parts kits (except the mag catch, specific to 9mm). Your trigger, pins, and buffer system install just like any other AR.
• Integrated Trigger Guard: One solid piece of aluminum. No weak points, no screws to strip out.

What You Need to Know

This is an 80% lower receiver. It is not a firearm. It requires machining to complete. You will need a jig, tools, and the knowledge to finish it. This is for builders who understand and accept the responsibility.

When you’re done, you’ll have a American-made 9mm lower that’s compatible with standard AR-9 upper assemblies. Perfect for a compact, hard-hitting pistol or carbine build that shares mags with your Glock.

Bottom Line: For $93.49, you get a no-nonsense, billet 9mm lower built with features that matter. It’s in stock, it’s ready to ship, and it’s built right. Order yours and get started.