RE: Looking for gun experts!
The previous posts have pretty well covered what could be wrong. Any good gunsmith can inspect your barrel to see if the muzzle has been damaged. If it is out of round, or needs recrowning, he can fix it for you! Merely BENDING the barrel would not result in a scattered grouping such as you are experiencing. All it would do is move the group center to a different point of impact. (Muzzleloader builders bend barrels quite often to get the point of impact to coincide with the line of sight.)
You may need a new scope. I don't know how rugged the current Simmons scopes miught be. The gunsmith can check it for you too. All he needs to do is put an optical collimator into the muzzle, and check the response of the windage & elevation adjustments to ensure they are moving the amount specified for each click......