Gas System Components Gas Tube – Pistol Length (6.75 in) Gas Tube – Carbine Length (9.75 in) Gas Tube – Mid-Length (11.75 in) Gas Tube – Intermediate Length (13.25 in) Gas Tube – Rifle Length (15.125 in) Gas Tube – AR-10 Long Rifle (15.5 in) Gas Tubes – Rifle Length +1, +2, +3 inches Gas Tube – Straight (17 in) Gas Block
