Welcome on your first post here, Fudd. You picked a nice sxs for your entry into the wingshooting sport. You question what the 28" M&F barrel arrangement is for. Pheasants and prairie grouse. You may be in the wrong end of Canada for that, but it also makes a nice duck gun if you shoot bismuth or other non-steel no-tox shot. Don't shoot steel in your full choke barrel. As for targets, it makes a nice trap arrangement.

Your receiver pins should not be drifting. It may be someone took the action apart and put the pin back in wrong. Have a gun-smith look at it...Geo