There is a few things I would check, on a break open style of rifle the locking mechanism can cause these kind of problems if it is breaking in and has any burrs or dirt of any kind where it locks together. Be sure it is seating all the way all the time. The scope mounts, check the torque, the rings make sure that one of the rings is not right up against the adjuster mounts for changing wind-age and elevation; scopes react badly to this sometimes. look at all your bedding points where the stock and the mechanism come together if one of them is loose it can cause your problem. Are you using the same measure and sabots all the time? Is your BP carboned up? Look at the end of your barrel is the button scratched or dented? These are the first things I would check. Lee