Mike's on the money here. When I was first taught pistol shooting 30+yrs ago with a single shot Webley 22 this was the way.
I believe most UIT shooting is done this way.
Six-o'clock sighting (where you set the sights so that lining them up on the bottom of the bullseye puts the pellet in the center) works best for targets since it gives a more consistent reference point than dead-on sighting
To be honest most of my guns now have Red Dot sights fitted.
Good luck, Phil