A sighting in tip without using boresighters and a lot of time.
Get yourself a range at 1000 inches. thats 83.333333333 ft. or 27.7777777777 yards. Works with scope or open sights. It will give you close to center at 200 yards. Thats what we used in the Marine Corps to set our battle sights. Also when you went to the range for Qualification first line of fire was the 1000 inch line. If nothing else it will get you well onto paper for final adjustments at 100 or 200 yds.