Its hard to say if the gun case caused your problems. The big thing is keep the rifle dry as possible while you hunt, and when you store it, do not change temperatures on it drastically. When cold steel is brought into a warm area, the steel forms condensation which in turn effects the powder charge.

It is claimed, you can put a rifle in a thick padded case and bring that into the house where it will warm up gradually to the house, but do not remove it from the case. Just make sure you wipe the outside of the rifle off real good before casing it. I personally never tried this but a friend of mine claims to do it all the time and claims he has no problems with ignition. He said the trick is to warm the rifle slowly.. it then does not condensate.

When I used to store loaded rifles over night, I put them in the unheated wood working shot. I stored them muzzle end down, resting that on some cotton cloth or a pile of news papers. That way if any moisture did form it would move away from the powder charge. I also took the 209 primer or #11 cap off the back end and tucked cotton around the opening. Again, I wanted it to catch any moisture that might form.

Also when you store a loaded rifle ... remember safety is very important. Keep anyone away from it that should not be handling it. They are a real temptation to children especially. Also I put a red bandanna through the trigger guard and tell everyone I see that the bandanna indicates a loaded rifle and not to be messed with....