Are you shooting this in a single-shot rifle or maybe an older Marlin underlever?
Sorry that I can't help you there with IMR3031 and 170gr bullets.
170gr flat nose load is usually Accurate Arms 5744 and 20gr for 1802 fps. THE load is 40gr of FFFg BP.
Got lots of data for the lighter bullets though - can't you whittle 'em down a bit?
tac