Thanks Younggun. I have been reading up on the Invector system, someone wrote that the plus system has a .740 bore while the old system has a .728 bore. It is supposed to improve patterns and velocity to some degree. I tracked down a modified tube and a wrench, it is supposed to have a full tube in it. I bought it because it was pretty, won't use it much because I don' use my old Savage pump much. Thanks again.