The Vang Comp System (VCS), designed by gunsmith Hans J. Vang, is a set of modifications to shotgun barrels. The alterations to the barrel consist of lengthening the forcing cone, back-boring the barrel, and adding compensating ports. With the VCS, accuracy significantly improves, felt recoil is dramatically reduced, and muzzle rise diminishes. By lengthening the forcing cone, the pellets have a smooth flow from the chamber to the bore. This prevents the pellets from bunching up in the barrel and reduces the felt recoil. In addition, the pellets do not become as deformed and keep a more consistent shape.