A boresighter should get you close enough to print a bullet hole on a large target at 50 yards if your scope is properly positioned. No boresight, not even a laser boresight, can help you sight in your gun. To sight the pistol in, you must fire it and adjust your scope accordingly. Every gun has its own personality. Even if the serial numbers are consecutive, no two are same. There's no assurance that a gun that shoots a certain type of ammo well would like it in the same way that another pistol does.
You will do well if you mount a nice sight on a good gun with good rings and bases, and select a specific type of ammo that it shoots well with a bullet that meets your needs. Purchase a case of the exact same ammo with the same lot number, keep it with the rifle, and make no changes.
Also, when your windage and elevation adjustments are in the middle of the allowable adjustment range, your scope is at its best. This is referred to as mechanical zero. Turn the dials all the way one way and then the other when buying a scope, counting how many complete and partial rotations there are, then divide that number and get the midway. For your tweaks, start there. Windage adjustments are available on many rear bases.