The Bushmaster XM15-E2S is a semi-automatic rifle built on the AR-15 platform. Designed for recreational target shooting, competition, predator and varmint hunting (where legal), and firearms training, it is chambered for 5.56x45mm NATO and is also compatible with .223 Remington ammunition. The XM15-E2S has been one of Bushmaster's best-known rifle series and has been produced in multiple configurations over the years.