gun finishes and rust

I recently had to store my collection with my mother while I moved. I just got them back and I noticed that the shotguns had light rust on them. My rifles are all fine, but 3 of 4 shotguns had light rust.

Is there a big diffrence in the finish of a shotgun as compared to a rifle?

The 3 shotguns were all remington 870's, two blued, one matte finish. The rifles are remington, winchester and ruger. I also had some cheap ak's in there that did not rust. The one shotgun that did not rust is on old ithaca that my dad had when he was a kid.


They were all wiped down and stored in one of the cheap steel safes from walmart.

muss