Re: Badger Ordnance rust
First: If you simply send it to BO, they'll return it to you in new condition. Whether they brush it, blast it, re-park it or replace it, you'll get a "new" one back. BO is first rate, and Marty is GOOD people.
Second: Unless you coat it, or keep it slathered in oil, it's gonna rust in service. Period.
Third: The mil-spec "coating" is not a coating at all, it's a surface treatment. It is called parkerizing, and while it will essentially never "rust out", it will get an orange haze, and still requires oil/ptotectant.
Fourth: While BO bears blame for delivering your part with rust on it, they've owned up, and told you they'd fix it. Sounds good to me. BO doesn't however bear any blame for you not liking the mil-spec park treatment.
Fifth: If you buy aluminum stuff, it won't rust.