If you're shooting subsonic (and probably suppressed?) at game, you'll want a flat point or hollow point for decent terminal effect. Unfortunately most .30 cal rifle bullets aren't that good in this scenario, giving extreme over-penetration with very little terminal effect, although there are some decent options in custom bullet molds.
Consider loading your bullets backwards, so the base becomes a big flat point.
Cast lead bullets are certainly easier to develop subsonic loads for, and what I generally prefer, although the Hornady 90gr XTP is worth a look for this application (for small game). It expands well at 900-1000 fps, and is easy to develop a quiet subsonic load with.
All said and done though, a .357 barrel for that contender would be a far better choice for your application, with a lot of good bullets that perform well in the velocity window you want.
