We recommend doing this work to every shotgun. For your money, this is the most cost effective thing to do to receive the best results in patterns and recoil reduction. The area in a shotgun barrel just in front of the chamber that directs the shot load into the bore is called the forcing cone. In most production shotguns this forcing cone is very short and at a very steep angle. We lengthen the forcing cone to 3 inches and and finish it with a mirror polish. By lengthening the surface, several great things are achieved:
Velocity is increased by reducing the sudden friction encountered with a short forcing cone.
Felt recoil is reduced because the reduced friction allows the shot load to smoothly enter the shotgun bore.
Pellet deformation is dramatically reduced because the shock of suddenly constricting the shot load is eliminated giving more even and dense pattern.
FORCING CONE LENGTHENED $75
( we do not lengthen the forcing cone on the Benelli 828U )