 This method is sometimes used by gunsmiths to implement a tighter choke on an existing gun without replaceable chokes, and can be done without requiring replacement of a barrel and without installing new screw-in replaceable chokes.Advantages claimed for a "jug choke" include improved patterns, reduction of recoil, and an increase of choke in a shotgun that does not have replaceable choke tubes.When a "jug choke" is implemented in an existing choked barrel, the bore inside the bored-out section of barrel effectively becomes "overbored", and this also typically lessens the amount of shot deformation, thereby increasing the shot pattern density.