Yote'
Airsoft will only fire 6mm plastic airsoft bb's. Most air guns, like those made by Daisy or Crossman will fire .17cal BB's or pellets, some will also fire .17cal darts.

flyinggoldfish
Semantics mainly! An airsoft gun is a type of airgun which has been specifically designed to be safe to shoot at people. Other types or airgun (which fire metal ammo) can be a lot more powerful and can cause injury and even death if fired at a person.