Now I know why.....

[rebAL]

NOT to store guns in case.  In just a matter of 2 days the inside of my barrel started to rust and it wasn't even raining; just condensation from leaving in my truck overnight.  Lesson learned!

[Graybeard]

Yup learned that lesson at least 40 years ago and it wasn't even my gun. I went to buy one from a fellow at his house. He had it in a plastic case and when he pulled it out for the first time in some while it was completely rusted up. Needless to say he didn't make a sale that day.

[DakotaElkSlayer]

  I was guiding grouse and woodcock with my Gordon setter on Drummond Island Michigan...  Broke down my SXS 28ga. and put it in a soft case hoping I might get a chance to do a little hunting myself.  Three days later, I pulled out the gun and had a nice quarter-sized rust spot on the case colored receiver.   I KNEW you don't store guns in a soft case, but hadn't a clue that a gun could be affected that quickly.

Jim

[corbanzo]

Yep, learned that from a good buddy of mine.  He had a 9mm he bought brand new just a few weeks before.  We went out shooting, he took it out of the soft case, and it looked dusty from all the rust spots coming up on it.  All it needed was a little bit of WD-40 to fix the problem.. but it never got stored in that case again.

[woodchukhntr]

I had a Ruger #3 in .22 Hornet.  In-between every-other-week uses I kept it in a soft case in my gun room in the basement.  I poened the case one time and noticed spots of rust on the receiver.  The damage was not much, but was a wake-up call.  I started using SS-2, which is similar to WD-40 on the guns after that.  Sure enough, I left in the case again when I was in a hurry.  After an extended time I noticed that it was in the case and opened it expecting the worse.  When I took the gun out, it had water droplets on the receiver, but no rust!  The SS-2 protected the finish.  I threw that case away.

[TribReady]

I'm joking a little bit, but this should be posted as a "sticky"
Great info---I knew it wasn't a good idea, but never thought it could be that dramatic and fast.
Thanks for posting for the rest of us.