Hi ultra mag,,,I check my acton screws before sighting in ,,every time,,,if the gun has sat (especially with a wooden stock) for a while ,,check em,,,,after shooting several rounds...check em,,,,a high recoil rifle will shake things up a lot,,,I have never had one come loose,,,dont use locktite,,,
the bigest cause of vertical (other than loose action screw--loose scope rings--loose bbl.--etc) is ,,,not enuff powder/pressure in the load,,,if the chamber pressure is low the powder will not burn properly,,,sorta like running your car with the choke pulled,,,,smokey case necks tell the tale,,,Roger