When you’re looking for Maxim Defense ingenuity in a new standard AR-9, the MD:9 is your answer. The MD:9 was engineered to fit the growing demand for cutting-edge AR9 style rifles for today’s military and commercial market. For increased comfort and versatility every MDX features our free-floating barrel with our custom handguard. These handguards provide a monolithic-like upper receiver platform and M-SLOT compatibility.