In Il2 it's more important to use nose mounted armament than wing mounted armament.
As in the real world, wing mounted armament is only effective close up and at, or close to, convergence ranges. Otherwise you may or may not be hitting with all of the rounds.
I flew in a "full real", no icons, no padlock, no external, server yesterday. Shot down 7 planes flyings the 190A4.
Shot down a variety of Yaks, LaGGs, and several other planes. In only 2 flights.
I guarantee you, I can get far more kills in the I16Tip24 than the Tip18 solely because of those cannons.
-SW