Been using a rifle bore sighter for about six years. Last year i mounteda lot of scopesfor folks and sighted in many more rifles.The laser bore sighter makes the job much easier. My adjustments are made at 25 feet on a one inch target paster on a wall. The difference between doing it with a laser boresighter and doing it the old fashioned way is the fact that the gun is usually on paper at 50 yards: The 25 yard sighting in isalmost always eliminated.The gun is usually zeroed at 100 yards after6-10 shots total.