Stainless steel still needs to be cleaned even though it is more forgiving than ordinary steel.

I went to buy a s/h single barrel stainless steel pistol in .50cal. The one tha Krank sells with a fibreglass butt.
The seller never cleaned it because he thought stainless steel was immortal! I have never seen such bad pitting inside a barrel as this one had. You could hang a piece of wire from one of the pits in the barrel.

Needless to say I did not buy it, in fact, it was so bad that he could not have given it to me