As I recall, federal officials are required to get the permission of a local Sheriff before they can do anything within a county. In the hierarchy of law enforcement protocol, a County Sheriff trumps everyone. This law is virtually never enforced though, but it is on the books.
It’s not enforced because it’s not true. I defy anyone to show me this anywhere on the books. The truth is that the power of the County Sheriff varies wildly from state to state.
Some states like Massachusetts, the sheriff isn’t even involved in law enforcement. The sheriff’s department there is relegated solely to running the jail, and acting as badged process servers.
Other places like New York and parts of Colorado, the sheriff isn’t even an elected official. It’s a largely ceremonial position, and the sheriff is appointed by, and serves at the pleasure of the mayor.
Other states like Alaska and Connecticut have done away with the position altogether and it simply does not exist in those states.
Reading this thread, it’s obvious that many FReepers have confused tradition with codified law.
You are correct, the Sheriff is THE CHIEF LAW ENFORCEMENT OFFICER for his County (or Parish). As such he can tell the FBI to take a hike. He also has the authority to authorize (or veto) possession of Class III firearms by a private citizen w/in his domain. Class III being fully automatic firearms, short barreled shotguns and rifles, suppressors, and sundry "destructive devices". Make a friend in the Sheriff and you too can play with "big boy toys".
There are several legal ways around needing his sign off on your form 4 if he should prove reluctant to sign, however they will cost more then just the $200 excise tax.