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This is a fully assembled lower receiver that gives you the foundation for a high-performance AR build. Franklin Armory machined it from billet 7075-T6 aluminum and finished it in hardcoat Type III anodized black for durability. What makes it stand out is the integrated Franklin Armory Binary Firing System, which fires one round when you pull the trigger and another when you release it. You can switch it back to traditional semi-auto mode with the selector if you want, so you get dual-mode versatility in one lower.
Not for civilian sales in: CA, CT, DC, DE, FL, HI, IL, MA, MD, NJ, NY, OR, RI, VA, and WA
The design philosophy here is practical. The flared magazine well helps you reload faster without fumbling, while the ambidextrous push-button QD sling mounts give you flexibility in how you set up your rifle. An integral cold-weather trigger guard gives you room for gloved hands, and there’s a serrated memory index point on the magwell so your trigger finger always knows where to rest when you’re not firing. The textured grip area forward of the trigger doubles as a support point for your off-hand.
You get the lower receiver pre-assembled with a B5 SOPMOD stock on a 6-position collapsible buffer tube, plus one Magpul PMag 30-rounder. A specialized tension screw eliminates upper and lower receiver play, so when you mate this with your upper, you get a solid fit with zero wobble. Franklin Armory manufactures these in Minden, Nevada, and they’ve been perfecting binary triggers since 2010.
The semi-auto mode delivers standard AR trigger performance, while binary mode gives you significantly faster fire rates. Controls are tight with minimal slop, and the flat-faced trigger breaks crisply despite the dual-function design. This lower works with most standard AR uppers and calibers, making it a smart choice whether you’re building a competition rig, a range gun, or something for tactical use.
The binary trigger fires one round when you pull the trigger and another when you release it, giving you two shots per trigger function cycle. You can switch to safe or semi-auto mode using the 3-position selector, which instantly disables the binary function. Even in binary mode, you maintain full control by simply switching back to semi if you need to stop or want standard trigger operation.
Yes, this lower works with standard AR-15 uppers. It’s designed to be the modular foundation of an AR build. The included specialized tension screw helps eliminate any wobble between upper and lower, so you get a precise, solid fit regardless of which compatible upper you mate it with.
The Libertas is a billet-machined design with integrated user features you won’t find on typical lowers. It includes a flared magwell for faster reloads, ambidextrous QD sling mounts, an oversized trigger guard for gloved hands, and a serrated memory index point on the magwell to safely rest your trigger finger. These practical touches add up to a more functional, ergonomic lower.
Yes, the B5 SOPMOD stock is already installed on the buffer tube, and the Ergo Ambi Sure Grip is on the lower. Everything arrives ready to pair with an upper receiver and start building or using.
This lower is multi-caliber compatible and works with standard AR pattern magazines, including the included Magpul PMag 30-rounder. It accepts 5.56 NATO, 308, 300 Blackout, and other common AR calibers depending on your upper receiver choice.
Absolutely. The binary mode is ideal for both competition and tactical applications where rapid fire and split-time control matter. The ergonomic design with ambidextrous controls and QD mounts supports whatever setup you need, and you can switch to semi-auto mode for match rules or preference.
| UPC | 818725013133 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | 0020023BLK |
| Action | |
| ATF Type | RECEIVER |
| Caliber/Gauge | MULTI-CAL |
| Capacity | 30 + 1 |
| Length | 16.3000 |
| Number of Magazines | 1 30 rd. |
| Package Height | 4.6 |
| Package Width | 8.2 |
| Product Type | Accessory-Lowers |
| Shipping Weight | 3.65 |
| State Restriction (IL) | NO SALE TO ILLINOIS PICA |
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