In pretty much every story of someone getting in trouble in an MV, it starts out with "I was minding my own business, driving to church, when I was harassed by the police for no reason". Later when the details come out the story becomes something like the guy in the M20 driving around firing the gas gun, or "But I didn't think anyone would be upset by me pointing a .50 at them in traffic, and the hand grenades I was pretending to throw were all fakes anyway!"
They didn't get in trouble for having an MV with a gun mounted on it, they got in trouble for displaying a marked lack of common sense and good judgement in what they were doing with it at the time.
The turret is unlikely to cause you any issues, but a mounted gun might. I know some states are less "understanding" than others, and that in every state there are going to be some badge-heavy rookie cops and the occasional Barney Fife who might freak out.
If in doubt, don't mount the gun until you get where you are going to.
And know your local laws about display of weapons!
In Texas, the key words for getting in trouble are "..in a manner calculated to alarm". This is interpreted in the courts as "Would a reasonable person be alarmed by the action". Not some snowflake, but a reasonable person.
So, in Texas if you walk into your local bar where everyone is a regular and knows you and y'all regularly talk about guns, you can walk in with a shotgun under your arm and proudly say "Look at my new fowling piece!" and you are not violating the law, because no one is likely to be alarmed by your action. Now, walk into a different bar where no one knows you and do the same thing - you're likely going to jail if you survive.
Cheers
