it is true that if you store your gun in a padded case it will rust?

Yes, if you live in a humid environment the padding will absorbe moisture from the air and rust your gun. If you live in a dry climate such as Arizona it's not a problem unless the padding is already wet.

I spray silacone spray in my cases to HELP prevent the rust .
I take the gun out and dry it off as soon as posible and use another case ,I dry that case in the dryer if nessery

Yes Tikka it is true. My nephew brought a lyman muzzle loader over to me that had been in a case for about 3 months. This gun was in bad shape with rust. It took me about a week to get the gun cleaned up and ready to reblue. I would suggest storing guns somewhere other then a padded case.