Andro Corp Industries 300 BLK 10" M-LOK Upper Receiver

300 Blackout was drawn up for exactly this configuration: a short barrel, a suppressor and a heavy bullet that still works when there is only 10 inches of barrel to work with. Andro Corp Industries builds this upper with a 10 inch 300 BLK barrel and an M-LOK handguard. Because the cartridge uses the same bolt and the same magazines as 5.56, the swap needs nothing beyond the upper itself. M-LOK slots handle lights and sling hardware, and the upper closes onto a standard AR-15 lower. Keep 300 BLK and 5.56 ammunition separated, since the two will chamber in each other's guns with bad results.