I will add, with my 835 I use the modified choke tube, nothing fancy, but it is a Carlson choke tube and my patterns with BB and #2 steel are tight at 35 yards. There is the possibility that if you use a full choke and large shot the constriction could cause barrel blow up or deformation, that is the reason for that warning. I have never seen it or heard of it and I don't experiment to try and find out either.