Depending on what I'm doing I like to use a high grade stainless like 303 or 316. I have easy access to this though because I am a machinist by trade and we have heat treating capabilities at work. Then I brush or polish depending on the situation. I like high grade stainless because of its extreme resistance to rust. It can be a b**** to work with sometimes though
Stainless is "sticky" when machining. But I love stainless!
I got to say after working with stainless for awhile you get used to the issues that come along with it. I also love aluminum but it is gummy also I hate how much of a pain in the a$$ it can be. We used to have problems with it building up between the flutes on the endmills But I love how easy it is to work with after the machining process. I was thinking about making some accessories for ar out of aluminum or composite to keep it light. We have been working with some incanel. Spell? And hasteloy. That stuff is a real pain you burn up tooling so fast. But its light and its good enough for aero space its good enough for me lol