I looked at a 556A1 locally this past weekend and really like the rifle. I did notice however that the rear sight slid front to rear freely on the picatinny rail even though it was tightened as far as it would go. This brings up the question, are the rails out of spec or the rear sight? I've never owned a Sig rifle so I'm no familiar with what issues they may or may not have. Appreciate it!

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