Airgun Corrosion

I had my gen 1 mrod fail because of corrosion after a year. Though nothing looked nowhere near as bad as the pics in the link. Nor was there any rust. Just some discoloration on the gauge and valve block. It all cleaned up just fine and was easy to repair. I was using a Benjamin hand pump and Im sure that did not help. I have moved on to a tank with a much better pump for backup. I do not want this happening to my much more pricey air guns. 
 
Aluminum will corrode, back when I flew my plane had an AD (airworthiness directive) that called for the panels to be pulled from different places on the plane and checked for corrosion. There was also an oil pump drive AD that required an engine tear down every X hours. Little planes are expensive to keep and cheap to buy....this is one reason.

The thing you have to remember, unprotected metal will rust starting right now.