Miami Rifle & Pistol Club: http://www.miamirifle-pistol.org/highpower_rifle.php
Central Indiana Highpower Rifle Shooters (Camp Atterbury): http://suemogle10426.wildapricot.org/
MRPC goes out to 600 yds and Atterbury to 1K
Let me know if you have any questions....
I forgot to add Lima Sabres, which has a nice 300 yd KD range: http://limasabres.com/default/HighPower.html
All of the matches at those three clubs (and just about any other that I know of) are open to the public. No need to be a member.