It will "happen" very slowly over the course of months, like the happening of summer and fall going by.
>pissed at a rabid anti-gun guy being appointed to the BATF
Don't be too pissed at Trump: almost no one can make it through approval process for a federal job at any high level.
That is why Trump has "hired" so many awful people.
OPM still plays a major role and that is one of Obama's strongholds, so appointees must be approved by Democrats unless POTUS wants to go to war for each one, and at this point he probably figures a temporary appointment of a stooge is manageable until he gets control of the hiring process.
When OPM finally shuts down, the real transformation of DC can begin.