Various Stainless Steel alloy's are available in reasonable quantities, each of which has a unique set of strength, machinability, magnetic and rust resistance among other characteristics.

Strength and machinability are the most important factors in my opinion as they significantly influence cost of manufacture and whether the mechanism will stay together when it goes boom.

All steel that I am aware of has a percentage of iron in its composition. Iron exposed to oxygen forms Iron Oxide otherwise known as rust.

A very minimum of care will prevent rust on SS guns and just a bit more care prevents it on non SS guns.

You will find that many if not all stainless steel guns have pins and springs made of conventional but high grade steel because Stainless is not suited to those functions.

Thank you for the very imformitive reply.

Since I'm not a metallurgist, I haven't seen every steel available. I can however tell you that I've not ever seen a stainless steel that could not eventually rust. I guess that's way they call it stainless, rather than stainnot.

Originally Posted by PhilR.

Since I'm not a metallurgist, I haven't seen every steel available. I can however tell you that I've not ever seen a stainless steel that could not eventually rust. I guess that's way they call it stainless, rather than stainnot.

My father always said that any form of steel can rust. So far he's been correct. A good, thin coat of oil goes a long way, though.

I'm also not sure if there is an iron alloy which is impervious to steel. I am aware of some handguns which are "significantly comrpised" of titanium. While rust isn't an issue here, price can be, and some suggest the recoil is considerably stronger in these lighter weapons.

Originally Posted by literaltrance

My father always said that any form of steel can rust. So far he's been correct. A good, thin coat of oil goes a long way, though.

I'm also not sure if there is an iron alloy which is impervious to steel. I am aware of some handguns which are "significantly comrpised" of titanium. While rust isn't an issue here, price can be, and some suggest the recoil is considerably stronger in these lighter weapons.

Even the ultralights that utilize Aluminum/Scandium and/or Titaniium alloys have to use steel springs and pins which can rust if not cared for.

None are rust proof.

Iron is an element.
Steel is an alloy of iron with carbon, (and other metals added for specific purposes).
Stainless steel is a group of those alloys. There are plenty. Some (like the stainless steel my exhaust is made of) rusts significantly. Others (like 316 stainless used in food preparation) I don't think "rust" as we commonly know it at all.

I did some food service work a while back and can say that without proper care the stainless counters, food slicers, spats, etc will all rust. The biggest reason you don't see it as often is they are constantly being cleaned and dried. It wont rust near as easy as some other steels. But that's why stainless restaurant stuff is pretty expensive. You will see in the cheaper brands of equipment that rust does occur easier.

Under the right conditions any metal will rust. That's why I protect my guns with Eezox or Break free CLP.
See test & decide for yourself: http://www.thegunzone.com/rust.html