Gtown78, just bought this choke...a Carlton flush mount in 680 to try in my 870 with longbeards 6's. Do you know the number it is putting in 10"? I don't like the extended chokes....if I wanted a longer barrel would have bought one. Just don't look or feel right sticking out beyond the sight bead....just me no problem with others using them. What length barrel you using....mine is a 26".