Bump for BKoenig's Post:
Summa you East Nebraska Gun Club members should invite bkoenig out to see your 600-yard range.
Which would probably be closer to his house than Hamburg Bend WMA.
He would probably let you shoot his .308 or whatever he's packing these days.
Just a Thought. Which is one of the benefits of this Very Fine Forum.
Been there, done that.

The thought has crossed my mind, but I think he was looking for a little more than 600yds downhill.
Brian, If 600 is OK with you, send me a PM, I'd be game for some range time.
As for Hamburg Bend, I would think that it is closed because of archery season being open for deer. Don't know, just a guess.