Next Level Armament Horus 9mm Upper Conversion Kit (8 in)

Next Level Armament's Horus 9mm Upper Conversion Kit turns a standard AR-15 lower into a 9mm carbine without a magazine well block, Glock-pattern magazines, or a fixed ejector. The upper uses a radial delayed blowback system with a bolt carrier group that resembles a standard AR-15 BCG, and the kit includes one 33-round CMMG AR15 9mm conversion magazine that drops into the normal AR-15 magazine well and holds the bolt open on empty.

Next Level builds the Horus upper on its Ascend Phoenix billet receiver, so it matches an Ascend Phoenix rifle, and it also fits other mil-spec AR-15 lowers. Next Level notes the Ascend contour occasionally conflicts with lowers that have large or extended aftermarket bolt catches; the NLX Forged kit avoids that. This configuration has a 8-inch barrel. Because the system depends on the AR-15 style bolt and the CMMG magazine, it will not run on a dedicated AR9 lower that uses a fixed ejector and a one-piece flat-face blowback bolt. It suits training on an AR-15 lower with cheaper 9mm ammunition.