[Brian Pfleuger]

Originally Posted by Picher

We used to not clean our varmint rifles during the season, but clean after it was over. One year, around 1968, I forgot to clean my .22-250 bore. It was stored leaning against a metal sanitary vent stack in a walk-in closet.



When I checked it the next spring, the bore was so rusted, I could barely see through it, much less run a rod through.



After much soaking with bore cleaner, etc., it finally would take a rod, and after copious cleaning, was found very pitted. It still shot well, but I sold it and got another.



This was in Maine where the stack probably condensed moisture on it's surface, but summers here are quite moist, so the bore surely started to rust then.



Bottom line...clean centerfire bores within a few days of shooting them, preferably the same day they're shot.

Summers here tend to be high 80s to upper 90s with humidity levels of 75% and up. I've never seen the slightest evidence of rust in a cleaned or dirty bore.

As far as smokeless residue being hygroscopic, I see little or no evidence that it is and some evidence that it's actually PREVENTS rust.