because condensation somehow magically penetrates the steel to get to where the powder is.
But "condensation" doesn't happen that way. All surfaces of a bore (as an example) can "condensate" moisture when the "dew point" is reached.
"Dew point" is a combination of available atmospheric moisture and ambient temp. Both are variables within a region and can change within 100yrds of a specific location.
(ever notice how the low ground has dew on the grass but the high spots don't?)(or how lakes an swamps have a fog in the morning,, but the road is clear?)
(except for them low spots)
Condensation usualy happens when there is a LARGE change in a temp swing and/or a change in available moisture.
Maybe I've just been lucky? But, I've never, ever, been known to be lucky.
I'm guessing it's just your circumstance, walk in the back door, put the gun in it's case in a corner near by,, good to go,(gradual)
If it's 20 outside and 72 inside,,
But if it's 10 and Mom's been in the kitchen canning or boiling potatoes for supper, and you bring that cold gun right up in there and put it on the counter,, that cold steel is gonna sweat. Inside and out.
Same thing with an olde "hunting camp or shack",, ya hunt all day, from can see too can't see, it's cold outside,, but ya know the cook's got the shack warm an food's ready come dark,, ya leave that gun sit in the porch.
I guess it's just sompthin we learn up here in Minn early on in life