Methods and apparatus are described for gas cylinder components for use with a firearm with a barrel. The gas cylinder component includes a reception bore for receiving the barrel. Additionally, the gas cylinder component includes a torque-proof fixture that is under pre-stressing, wherein the torque-proof fixture comprises one or more bores tangential to the barrel further including a pin to create spring pinning action. Further, the gas cylinder component includes a foresight that is rotatable around an axis, and a demountable clamping device that secures at least one position of the foresight. The gas cylinder component is under spring pre-stressing and is torque proof on the barrel. Additionally, the gas cylinder component is to lock on the barrel. Further, the engagement of the gas cylinder component on the barrel is to substantially prevent the rotation of the gas cylinder apparatus relative to an axis of the barrel. Further yet, substantially all forces that are introduced to a front of the firearm is absorbed by the gas cylinder component and introduced into the barrel.