Whenever I put the chain sprocket cover over my bar and chain and tighten the nut it does not hold the bar in the correct alignment position. As the nut begins to really tighten , back of the chain sprocket cover moves away and prevents it from flush at the very back near the muffler. This results in the bar/chain not fitting flush or flat and cause a misalignment with the sprocket. This puts the chain is in a bind and will not move . I do have the tension in the hole in the bar correctly. I guess you could say that it just seems not to fit correctly. Anything suggestions I can look for. I do know it is the old 015 that does not cover the muffler. Thanks