Quoted:
How the Hell??? The beretta is suppose to be melonite (tennifer Glocks trade name for it) coated... The ones we were issues the M9's never rusted they sucked but they never rusted. Even with the black paint coat mostly gone and holstering into a sandy holster still 0 rust. I think the slide might be defective or he did something to really punish it.
This is SO wrong.
Beretta uses Bruniton on the black models. But only on the slide. The barrels are not bruniton'd, and the frame is just anodized.
However - that is the black models.
The stainless models are just plain stainless steel for the barrel and slide. The frame is still aluminum and is still annodized - just a different color.
Foam attracts moisture. I have seen a lot of stories of handguns and long guns rusted by keeping the gun in the case, locked.
Some of this can also depend on the humidity in your area.
I would suggest NP3 - it is a new coating that will honestly make the gun rust proof. Its the most rust proof finish out there. It is a grayish color finish. I'd do the frame too, so the whole gun matches.