With a scope and a rock solid rest/clamp, you can get one sighted in faster than with a bore sighter, which are notoriously inaccurate. You can do it with open sights too, but it’s not as easy or accurate. Put the gun on a rest, where it cannot move, and then take a shot at the target. Make sure the gun doesn’t move at all, and adjust the sights/scope POI to match where the bullet hit. Your second shot should be very close, if not perfect.
It really takes a very good gun clamp for this, but you could get close with a decent rest.