I've recently solo'd Raxgore three times in a row with AP (I get my nuke locked and keep Righteous Seal and Commandment, although I've heard recently that using a scroll that damages him will also get that locked and you can keep your skills so that's something I'll try.

As AP stands, last I heard the rank 10 Passive is still bugged so it's not at 100%, but it's the best tank in game right now.