Airsoft barrels and hop-up units are essential parts to your AEG. Hop-up units, which include the hop-up chamber and bucking, ensure that each airsoft round gets the right amount of backspin for it to reach its target. Inner barrels can fit in different airsoft rifles — from compact M4s to AK47s — of different lengths. Airsoft Megastore also offers tighbore barrels up to 6.01mm in diameter. Buy your inner barrel and hop-up unit at Airsoft Megastore today for some of the lowest prices on the market!