<... maybe I am a racial profiling prejudiced bastard ...

You are, but then, so's everybody. We just need to be able to check ourselves, and you did fine -- though I would have shot better.
;^)

... I went out shooting at the gun range today ...

And a little military training could cure you of this error. If the target is only 100 yards/meters off, then you were more likely at a rifle range. For my gun in my Infantry days, the targets were often out of sight, and about 1 to 5 kilometers away.
;^)

Dan
--ps--
The call was right. Too many would simply have turned the other way. You saw what you believed to be illegal weapons in use on a public range.