When considering replacement of the iron sights on your pistol or rifle, there are some measurements differences you must be aware of to prevent frustrating mistakes when placing orders.
Likewise, when adjusting iron sights, understanding which direction to move front and rear sights to achieve the desired aim point can be confusing to new and seasoned shooters, alike.
The first thing to understand is that sight height is measured differently on pistols than it is on rifles. The height of pistol front sights is measued from the top of the slide to the top of the sight. This differs significantly from rifles where front sight height is measured from the bottom of the dovetail to the top of the sight.
So, now you have your new sights, they are the correct height, and have been installed on your firearm. But when shooting at your target, you notice the point of impact is low and too far to the right. Which way should you move your sight to correctly move the point of impact?
Most firearms make sight adjustments by moving the rear sight. When adusting rear sights, you move the sight in the same direction you want the point of impact to move. In the above example, you want the point of impact to come up and move to the left. So, when adjusting the rear sight, you want to raise the front sight and move it to the left.
Some firearms (i.e. AK-47) make sight adjustments by moving only the front sight. Using the same example above, to accomplish the same point of impact correction, the movement of the sight is exactly opposite of what is done with rear sights. To move the point of impact up and left, the front sight must be moved right and down.