Caliber: 9mm Luger. AR-9 lower receivers with last-round bolt hold open compatible with 9mm service pistol magazines for Glock, Beretta, and Wilson Combat EDC X9. Accepts standard AR accessories. Integral triggerguard, flared magwell. Closed-bolt blowback operating system. Match-grade button-rifled 1:10” twist barrels. Introduced 2016. SEE POLITICAL PANIC PRICING.