Why do shotguns rust?

[MidnightSon117]

I have an 870 Express and a Benelli M3 next to each other, and my room is really humid because of all the moisture from Skyline. No rust whatsoever.

All I do is take the pink cloth for removing rust found at any gun store, rub it down, and then I take the yellow Kleenbore rag treated with silicon and wipe it down. Even with handling and shooting, it stays rust free.

Maybe a dog is peeing on yours?

[coop44]

hot blueing is a controlled form of rust, done with specialized salts at 300 degrees. As such it does very little to prevent rust. It's all about maintaining your firearms and storing them properly.

[TRAP55]

Bird blood will eat a hole in the finest shotguns, within a very short time! The salt in their blood is more corrosive than the salts in corrosive primers.

[NeoWeird]

It might also be the alloying content of the steels used.

Since rifles opperate at a higher pressure range they usually are made of higher quality steels; particular alloy steels specifically designed for ordnance, aviation equipment, etc. These allows contain other metals like Chromium, Molybdenum, Vanadium, Tungsten, Nickle, etc. which in turn are rust inhibitors or won't rust at all. So while it may not be stainless steel (which WILL still rust), it is a step towards stainless steel and as such exhibits signs of rust less quickly than other steels.

Shotguns, and to an extent rimfires, on the other hand can probably get away with low carbon or even mild steel in many of their parts. These steels lack the rust inhibiting elements that prevent rust formation so it would stand to reason that they would be more susceptible to rust. I'm no metalurgist, but I've been told by people in the metal industry (but who themselves are not metalurgists either) that the stronger crystaline structure formed in steel by case hardening and heat treating creates a more difficultly broken down structure than annealed steel or soft steel. Supposidly this doesn't prevent rust, but it makes it much more difficult to form.

Both of these factors probably play a role in rust forming on shotguns faster than on rifles.

[M1A Rifleman]

Blueing is like being married to a beautiful woman... the prettier they are the bigger pain in the a** they are to maintain.

[floogy]

oxygen

[eccvets]

its more then oxygen, you had better go back to your highschool chemistry class dude...

[floogy]

Ok, I know that but basically, oxygen.

[NeoWeird]

Dude, I thought trolls came out from under my bed, stripped off the steel for their bridges, and left red goblin poo in it's place that dried and became rust...

Or am I mistaken?