copied this from the web:

Lengthen Forcing Cones - $75.00 per hole...

Briley Manufacturing offers long forcing cone gunsmithing. Need Long Forcing Cones? We have full time gunsmiths ready to assist you. Long forcing cones can improve your shot pattern.

How far can we lengthen your forcing cone? That depends on your shotgun. Each is unique but a better pattern is almost always certain...

Has anyone ever had the forcing cones lengthen in a shotgun barrel? If so, care to relate your experiences here...

Last edited by ed good; 11/05/13 12:21 PM.
keep it simple and keep it safe...