Never run out of ammo
This is quite simple and does not require a lot of work. To never run out of ammo in a mission after you kill a Nazi pick up his MP40, MP44, or Kar98. They are the German weapons and all enemies carry one of the three. After you have 2 of these(I suggest the MP40 and the Kar98 because then you have a rifle and a powerful SMG.) you can just kill the Germans without having to worry about ammo because when you run over one of the dead enemies you pick up his ammo.
Added by: Brandon 2006 Aug 5th 2006, ID#349