It is best to utilize attachments so that it is possible to endure in gun battles at any distance.
For instance, using a Vcog or Acog scope with a canted iron/delta sight. This will take care of long and short distance gun battles.
You could also use a small sight such as the Coyote sight with a ballistics tracker, so it is possible to snipe with such a defective scope. It will also help with short distance gun battles (goes without saying).