This is a great gun.  It's a Century Arms L1A1 Sporter rifle, made from surplus inch-pattern parts and fitted to a Metric receiver.  It has a shortened barrel (16.5") and a muzzle brake on it, which I think really improves the appearance of this gun.  This is probably one of the easiest of my semi-autos to clean because all the internal parts have a chrome plating on them, which allows the crud to wipe right off.  This one also has one of Buffer Technologies' recoil buffers installed.