My carry on has always been my backpack, complete with binos, range finder, and all the trimmings, except knives, which go in the guncase with the rifle. Never a problem with Delta or SouthWest
I would always carryon any optics. Last time I flew I had 2 binoculars and the little ED50 in my carryon. The XRay guy had to take a look at that for a moment. Not too many going through with that.
I just went to England with a rifle scope in my carry on, didn't have a problem state side but got stopped in London. Five minutes later I was on my way.