Bushnell Professional BoresighterThe Bushnell Professional Boresighter is an essential tool for quickly adjusting scope or iron sights to align with the rifle or handgun barrel. Correct use of your Boresighter will put sighting in test shots on the paper, requiring only minor expenditure of time and ammunition by test firing to achieve pin point zero at a given distance. Because of the many variables involved in both ammunition and the firearm itself, final sighting in must be done