The factory chrome lining in the restricted VZ is very resistant to the corrosive ammo, i know all of you are going to cringe when i say this but i didnt clean mine, honestly left it 4-5 months before i dug it out again, and the only place there was any corrosion was at the very end of the barrel where the compensator screws on, and it was fairly pitted there, the barrel and rifling was perfect yet, no corrosion in the gas system either, i was very impressed, ive been thinking about buying a non-res and sending it to rauch, i hope his finish stands up as well as this one
EDIT: its also stored in a safe in the basement on a 2x4 base on bare concrete floors, so its fairly humid, i have a dehumidifier running but it cant keep up