I got Little Bird in early March, upgraded to Buckaroo around late May, and then just waited for shadowtech (Scarab etc). Worked for both my first blackbeard run and the current jack sparrow one. I started in EA both times, which makes necroplane parts (which you need to get 14mm ammo from) a bit more common than usual though.
Never used anything other than 14mm ground chainguns and 25mm light ones either.