Though rarely ever made of iron
as it will rust very easily, "iron sights"
is still the term used to refer to the notch and post
sights that firearms commonly come with. It is a very simple sighting system but it sure does work.
A common misconception is that long range shooting is impossible with iron sights and one will need some sort of optical device like a rifle scope, the truth is scopes only help magnify the target but the bullet will fly just as straight, and just as far and true with or without a scope. The limitation on iron sights is on the user and his/her eyesight, not the rifle.
There are documented stories of WWII snipers that had confirmed kills of up to 300 yards distance with just iron sights on their rifles.
As a starting point in learning to shoot, the use of iron sights is a must. Learn to use this properly before you move on to using scopes.