I was never good at shooting iron sights with a post front, and find that an aperture front sight makes shooting more accurate and much less tiring.

Here's a picture of an aperture front sight I made on my kitchen table with a hacksaw, file, drill and Bernz-O-Matic torch. The brass washer is soldered into a slot in a piece of brass-both from the local hardware store. The flat piece of brass is filed to fit the sight base and drilled for the pin. When finished the front of the washer is blacked with a magic marker, and the aperture front sight is done.

It is easy to make apertures for rear sights on military and sporting rifles by gluing or soldering a washer to the rear sight. I don't have an example to take a picture of, those guns have gone down the road. The aperture rear sight is ideally located close to the eye, that isn't where this aperture is, however I've found that the aperture way out there on a military rear sight helps me a lot.