Nexus Firearms Kuna Billet Lower (PMAG EV9 + AR-15 FCG)

Nexus Firearms' Kuna Billet Lower is the single most impactful Kuna upgrade available. Factory Kuna magazines and fire control components are both proprietary. The Nexus lower replaces the polymer factory lower with a billet aluminum unit that accepts Magpul PMAG EV9 Scorpion magazines and standard AR-15 trigger, safety, and pistol grip.

Nexus is explicit: this lower works with Magpul PMAG EV9 magazines only. Other CZ Scorpion EVO magazines do not feed reliably because of the Kuna's bolt geometry. If PMAG EV9 availability ever dries up, the lower loses its magazine advantage.

Two variants are sold. The paddle-release version is $349 and puts the mag release at the front of the trigger guard in AK/Scorpion style. The push-button version is $374 with an AR-style mag release on the left side of the lower. Both ship with a fully ambidextrous bolt release, a captured takedown pin, a safety selector spring shim, the mag release, and an install manual. The lower's trip kit dropdown offers two options at checkout: a Rare Breed FRT L3 trip ($99.99 standalone) or a Super-Safety trip ($79.99 standalone). Both are sold separately by Nexus as well, so buyers can convert a standard lower later. The buyer supplies an AR-15 grip, safety selector, and trigger.

The upper receiver is the serialized portion of the Kuna, so this lower ships directly without an FFL transfer. Lead time is 6-8 weeks per Nexus, and cancellations carry a 10 percent restocking fee. Sold in black hardcoat anodize (standard).