I was shooting ball-ets out of my Renegade (1-48 twist)the other day and had to use a short starter to get them going. They seemed a tight fit. Whether the same would hold true in your rifle is hard to say. Since you have a 1-60 twist you are going to be limited a little to roundball and short conicals I think. In my 1-66 twist I shoot roundball, the lightest ball-ets, and like you, I want to try some PA Conicals but I think they are a lot like a ball-et actually.

How does the rifle group roundball by the way?