I see. Shady post offices!
NiteWalker, really....it's NOT the Post Office's "shady practices". To be honest, it's Brian who has the "shady practices". I don't know the definition you use, but router bits wouldn't seem to fit any reasonable-thinking human being's definition of "media".
The acceptance of the media mail shipping also entails agreeing to the possibility of having the package opened to verify its contents and being billed for the actual cost of shipping. If the bit sets were to be refused and sent back to him, Brian would have to pay that amount (if there is a return address on them).
my post office is the one that won't let me send DVD's or video games media mail either and they open every package I ever tried to send media mail, natzis!!!!
You need to find the law as it is written, walk in with it, then raise holy hell about being able to send DVD's. They most CERTAINLY fit the description laid out about what actually would constitute media mail, and I've even walked in with the box open on my first media mail venture and asked the guy working the counter (not some shmoe temp either, an actual Post Office employee, in case anyone might be thinking that).
Guy laid it out for me - sending CD's, DVD's, books, and some other stuff I didn't pay much attention to are most definitely considered media mail, and your local post office either is being a purposeful ass to you because they don't think you can find the law (or don't want to explain it to you), or you simply don't fit under the guidelines for those things due to other problem-causing issues you haven't been clear on, like you're sending everything all at once, sending eleventy brazillion pounds of stuff, etc.
No matter what, your story seems to be missing some things in the translation, because at least one thing you mentioned wanting to ship is most definitely considered media mail.