By SafeArmsReview| From YouTube.com
Because of the vertically arching travel of the 5.56mm NATO round, it is common to use the following procedure to zero your “carry-handle equipped” AR-15 using the following procedure established by the US military.
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This video was originally posted at http://www.youtube.com/watch?feature=player_detailpage&v=j5QCGWYfHWk
Printable zeroing targets for download can be found at: