Tiger Valley does alot of stuff.
I believe that the austinrifleclub.org has up to 500yd shooting every Wednesday. It is a private club, but they're trying to grow the membership.
ARC goes out to 340 yards on Wednesday. That's a good enough distance if you ask me. For a challenge, and mimicking the ballistics of more powerful rounds at longer distances, you can always try your hand at .22 LR at 300 yards.