The situation described in Arkansas sounds similar to one I know of in my state. There is a bit of the "old boy" network involved.
There is a ret. LEO in my area who "owns" a Tommygun. The NFA one, not the semi auto that is all I (as a mere private citizen) can own. Now, this gentleman "owns" the machinegun, keeps it at home, and when the acitve duty cops want/need it, they go to him and "borrow" it.
There is no way to get around going through the Feds to legally own a machine gun, anywhere in the USA. Period.
However, while this old boy owns the gun, and everybody knows it, on paper, the POLICE DEPARTMENT owns it, and he just stores it for them. The old boy is retired, meaning he doesn't put in scheduled hrs on patrol or at the station, but he is listed as an active deputy, and will be until they close the lid on his casket, I think.
Is it fair? Is it something any of us could do? I don't think so. But it is within the letter of the laws. Many NFA owners get some level of police creds, to allow or ease their ownership and purchase of NFA arms. If your local chief LEO is cool with it, maybe you could do it too. It is entirely a local thing and all about who you know, and how well, and what they are all willing to do for you.
And its not corruption, per se (although there might be cases where corruption also involves NFA ownership/permission), its within the law, just like the "gunshow loophole" (which we all know isn't a "loophole", its simply obeying the law, as written).
If your particular jurisdiction allows for it, its ok. Not very fair seeming to the rest of us, but legal. IF the jurisdiction doesn't allow it, then even though still legal, its not permitted.
It may seem to be a legal fiction, but if its legal, then its not really fiction, is it?
All else being equal (and it almost never is) bigger bullets tend to work better.