Unfortunately, your experience is quite common. I know of one case where 4 (thats right, four) different 28 ga guns were shipped to a customer with doubling issue. All of them did it!!!!!!! These guns are manufactured by Kahn in Turkey, and used to be sold under that name. Both of the 12 gauge guns my father-in-law had doubled, even after being sent in for "repair". This is rediculous. EVERY one of these guns I have been exposed to has doubled. Mossberg customer service isn't much, and they will all be out of work when the lawsuits start rolling in................The issue is well documented