The forend on my model 12 is a little loose, it rotates some. When I turn the collar at the front to tighten it there is a groove that lines up with the barrel. The problem I'm having is when it's lined up it's not tight enough and if I tighten it more it doesn't line up with the underside of the barrel and it won't go another full turn. Any ideas? I hope I've explained it well enough because I'm not sure if I'm using the right terms. Thanks, Mike.