Am I incorrect in my belief that shooting leaves a corrosive residue that would ultimately ruin a barrel? Living by the ocean, I know proper storage is important. My Craftsman wrenches have rust just sitting in a tool chest. Some how I believe that storage of a fired gun was like leaving the gun unprotected and the gun powder residue was corrosive like salt water. I think I am incorrectly confusing the two ideas. I welcome any comments.

Leaving a dirty black powder gun or any fired with corrosive primers uncleaned will pit and rust the barrel. With modern powders and primers it should not be an issue, even in a humid environment...but keep everything cleaned and oiled so you don't have to worry about it.

PS Living by the ocean in So Cal - they haven't run you out of town on a rail for being a gun owner? Surprising!

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Alan
SWCA LM 2023, SWHF 220

If you don't want to clean the gun, like you take a few shots and put it away. I'd run a patch with some oil down the innards and wipe a film on the outsides. I know that the beach plays havoc on piano works. I'd bet if a gun were in a closed box it wouldn't corrode at all, but why take chances? I don't live near the beach and keep a little oil on my guns.

PS I'll bet a lot of people will recommend advanced anti-rust compounds but to me a few drops of oil goes a long way.

I do not know about all possible combinations of gunpowder and primer - but from what I have seen in my admittedly short time as a gun owner but voracious reader is that primers labeled as corrosive have a compound in them which when burned results in a salt being created which will leave residue in your barrel and possible get into the chamber and other areas as well. By itself this is not such a big deal but combine it with moisture and now you have a potential problem where surface rust can form rather quickly and pitting can occur not long after. Exactly how serious this problem is will depend on lots of factors such as humidity and temperature and how many shots you have fired etc.
Any residue - even those without salts - especially if the residue is hygroscopic - then moisture can build up on your barrel and cause rust - though likely at a slower rate than salt water.
I'd imagine that some barrels, say lined with chromium for example, will be affected less - or resist rust loner.
Most modern primers do not use corrosive compounds - but they are common in military surplus ammo, especially those with Berdan primers.
When using corrosive primers or when storing in high humidity if you cannot do a proper cleaning a quick swipe of the barrel is a good idea - and for longer term storage there are plenty of discussions on that topic.

I always start cleaning my guns at the end of the day (range or hunting). I am probably as concerned about the residue left from contact with your skin. Some folks have higher salt content and the exterior of a blued gun will begin rusting in less than 30 minutes after contact.

The residue left from burning powder with non-corrosive primers leaves at least carbon behind. Carbon can collect moisture and after firing the oil has burned away. So how long do you feel comfortable with moisture in the chamber and bore of your treasured firearm?

As previously mentioned, if you don't want to clean, at least put a protective oil coating on surfaces that need protection.

It's been my experience that any gunpowder residue will absorb moisture and cause rusting. During the summer I make it a habit to store fired guns in a low humidity area of the house, or run a patch down the bore and wipe the outside down with an oily cloth.

Here in louisiana when finished shooting either rifle or pistol I always run a wet hoppe's patch down the bore. I have a rem sendero in 308 that one time I forgot to put a wet patch through. Now I only live about 45 minutes from the range. In that short time after I got home a wet patch was almost impossible to run through the barrel. so used a wet brush first to loosen up some of the carbon fouling. I use one of those plastic face cream jars with patches soaked in hoppe's. I had the opportunity once to see a muzzle loading rifle that had not been cleaned after firing. Should have got a tetnus shot before I picked it up and shined a bore light down the barrel. Guy didn't live far from my house so he brought it over to see what could be done about saving the barrel. removed the barrel from the stock and clamped in a padded vice. Shot some kroil down the tube a lot of kroil. Had it coming out the nipple. I used one of the tornado coiled stainless steel brushes to try and get the heavy stuff out. Also took the nipple off as well. Once I got the bulk of the crud loose blew it out with the air compressor. light down the barrel showed light pitting almost evenly through out the bore. Then copper brush on a shotgun rod. back and forth strokes. After doing this started with patches. All using kroil. At this point we are dealing with the rust. Must have used a good 40 patches. They were not pretty to look at. By the time I finished about and hour and a half we were down to the pitting. Really soaked the barrel in froil this time and left it overnight.While that was going on using some 4-0000 steel wool and some oil managed to safely remove the rust from the outside of the barrel. Next morning repeated the scrubbing routine prior to calling this guy up. Things started to look up as patches were coming out cleaner and no rust. One more shot of kroil and then a blast again with the air compressor and that was it. did i get all the rust out? probably 95% or better. Told him to get some kroil and when finished cleaning after shooting really spray the inside of the barrel.He told ne he had only fired about fifty shots and I told him doesnt matterhow many shots you fire it's what ends up in the barrel when you are done. So mow he caries persoaked patches in his shooting kit.Frank

Modern powder and primer residue in and of itself is not corrosive, but as above, moisture from the air can infiltrate under the fouling and cause corrosion.
The first sign of trouble is when some of the fouling flakes off exposing a pit in the steel.

Either cleaning the gun or at least running a patch with some rust preventing lubricant like CLP Breakfree through will prevent damage.