I'd bet the shellplate is steel. But whatever it's made of, you rarely hear of any Dillon part breaking, and when you do it's usually some fiddly little thing in the primer feed system. Never a major structural component (except the frame that got shot up in a gun store holdup some years ago - Dillon relpaced that under warranty too
) And as Rivers observed, Dillon's customer service is legendary for replacing stuff after only a toll free phone call, no questions asked. So pick the model that suits your needs, and enjoy the experience. Dillon fans are legion, and they can't all be wrong in their enthusiasm
.