Mid-Length Gas System
Mid-length gas systems are pretty flexible configurations for an AR-15. Generally found on rifles with 14.5-16in. (36.8-40.6cm) barrels, the mid-length gas system will keep the rifle reliably cycling while also reducing felt recoil since only the necessary amount of gas to cycle is being forced into the gas tube, unlike a carbine-length gas system on a 16in. barrel. The mid-length gas system is also a bit more reliable than a "dissipator" (rifle-length gas system AR with barrel chopped to 16in. (40.6cm) since the gas block is just slightly closer to the chamber than the muzzle, thus allowing a bit more gas to enter the gas tube to ensure reliable functioning. Mid-length gas tubes are generally 11.75in. (29.8cm) in length and use 9in. (22.8cm) handguards. The mid-length ARs that have been reviewed thus far can be seen listed below.