1st, they were trespassing in the gravel pit (not a target range as you first stated), 2nd they were reported by nearby residents who felt they were in danger from stray bullets zipping around their property.

The NRA doesn't "encourage people to own guns". They/we (I am the NRA) defend the rights of gun owners and promote responsible and safe shooting.

Obviously, the deputy, in his judgment, thought something was suspicious and had the presence of mind to take their names. Who could blame him so shortly after 9/11? Not only their dress, but also something in their actions must have caused the deputy to take note.

Profiling maybe.

More like putting 2 and 2 together.

As far as the FBI's case goes, let's wait and see.