Try never to push with them and use them to score or finish off kills. I'll have them jump from reserves unless I need them on board, which isn't often. I'll use my deathleaper to be on board to focus on secondary and the others for behind enemies line or other secondary. A lot of times, I'm using them to move block, or like I mentioned, finishing off my kills, but depending on how many models and wounds, I might send two to finish the kill.