RE: Hornady SST or PR Dead Centers
The Hornady SST's will get good expansion. If you have doubts, soak a stack of newspaper and shoot into that with your load. You can peel open the stack of wet paper and it will show you the expansion that is taking place. I Dead Center is a pure lead bullet if memory serves me, with the poly tip. So I am sure you are going to get some good expansion with them also.
The SST's have taken a lot of game down. If I were shooting those kind of groups with that powder charge.. the old saying, "don't mess with a good thing".. comes to mind.