Mine do a lot better off the bench too.  I was getting groups a bit larger than yours off the bench, but at Camp Perry was hitting 8s and 9s.  But that was another 92/96 that hasn't had much done to it.  I did get the lower band of it tight to the wood so that it doesn't tilt when pressure is put on the sling.  With the upper band, I've found there is both too tight, and too loose, and that pressure is going to change as the barrel warms.  If you pull on the forearm, behind the band, and feel a little movement, or hear a click as you alternately pull and push, it's too loose.  Since you have 5 sighters, start your groups after warming the barrel with 5 rounds, see how that works for you.  I'd certainly not mess with the receiver ring inletting as has been done to my other one.  I found out that if you overtighten the front guard screw when that's been done, you get cracks at the rear of the magazine inletting as that round receiver is pulled down into the inletting.  I have those cracks stabilized with injected epoxy now and the front screw is just snug.  Perhaps this year it will get to take the trip to Perry with some .310" diameter bullets to match it's .310" groove diameter.