Patent ID: 8468929

Claim:
A firearm having a gas piston system, the firearm comprising: a lower receiver, an upper receiver mounted to the lower receiver, a barrel mounted to the upper receiver, a handguard surrounding at least part of the barrel, an elongated mounting rail defining a first side and an opposite second side, the elongated mounting rail positioned above the upper receiver, the upper receiver mounted to the second side of the elongated mounting rail, a gas piston housing operatively mounted to the barrel and positioned forward of the upper receiver, the gas piston housing slidably mounted to the second side of the elongated mounting rail, a piston and rod assembly operatively mounted to the gas piston housing and positioned above the barrel, the piston and rod assembly operatively connected to a bolt carrier disposed in the upper receiver, and a charging handle operatively connected to the bolt carrier, wherein the elongated mounting rail extends above and across and mounts and aligns the gas piston housing, upper receiver, and piston and rod assembly.