The BCM M4 Mod 0 Carbine is an AR-15 style direct gas impingement semi auto rifle that has established itself as the gold standard in the firearms industry. BCM leaves nothing to chance using components and parts that are beyond the Mil-spec level which really boils down to a minimum standard. BCM goes beyond the minimum standard by making a commitment to individually inspecting every component that goes into their rifles. While other manufacturers cut corners and save cost by batch testing parts the provide you with the quality of rifle you pay for. Stop settling for inferior lesser quality products and pick up a BCM AR-15 semi auto rifle today.